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1.  Substrate binding of a GH5 endoglucanase from the ruminal fungus Piromyces rhizinflata  
The structure of a complex of an endoglucanase with cellotriose was determined with a hexagonal unit cell and showed how the substrate interacts with the enzyme.
The endoglucanase EglA from Piromyces rhizinflata found in cattle stomach belongs to the GH5 family of glycoside hydrolases. The crystal structure of the catalytic domain of EglA shows the (β/α)8-barrel fold typical of GH5 enzymes. Adjacent to the active site of EglA, a loop containing a disulfide bond not found in other similar structures may participate in substrate binding. Because the active site was blocked by the N-terminal His tag of a neighbouring protein molecule in the crystal, enzyme–substrate complexes could not be obtained by soaking but were prepared by cocrystallization. The E154A mutant structure with a cellotriose bound to the −3, −2 and −1 subsites shows an extensive hydrogen-bonding network between the enzyme and the substrate, along with a stacking interaction between Trp44 and the −3 sugar. A possible dimer was observed in the crystal structure, but retention of activity in the E242A mutant suggested that the enzyme probably does not function as a dimer in solution. On the other hand, the first 100 amino acids encoded by the original cDNA fragment are very similar to those in the last third of the (β/α)8-barrel fold, indicating that EglA comprises at least two catalytic domains acting in tandem.
doi:10.1107/S1744309111032428
PMCID: PMC3212359  PMID: 22102024
carbohydrate utilization; catalytic domain; cellulase; molecular interactions
2.  Structure of Stenotrophomonas maltophilia FeoA complexed with zinc: a unique prokaryotic SH3-­domain protein that possibly acts as a bacterial ferrous iron-transport activating factor 
The crystal structure of FeoA from Stenotrophomonas maltophilia has been determined to a resolution of 1.7 Å using an Se single-wavelength anomalous dispersion (Se-SAD) approach and revealed a unique dimer cross-linked by two zinc ions and six chloride ions.
Iron is vital to the majority of prokaryotes, with ferrous iron believed to be the preferred form for iron uptake owing to its much better solubility. The major route for bacterial ferrous iron uptake is found to be via an Feo (ferrous iron-transport) system comprising the three proteins FeoA, FeoB and FeoC. Although the structure and function of FeoB have received much attention recently, the roles played by FeoA and FeoC have been little investigated to date. Here, the tertiary structure of FeoA from Stenotrophomonas maltophilia (Sm), a vital opportunistic pathogen in immunodepressed hosts, is reported. The crystal structure of SmFeoA has been determined to a resolution of 1.7 Å using an Se single-wavelength anomalous dispersion (Se-SAD) approach. Although SmFeoA bears low sequence identity to eukaryotic proteins, its structure is found to adopt a eukaryotic SH3-domain-like fold. It also bears weak similarity to the C-terminal SH3 domain of bacterial DtxR (diphtheria toxin regulator), with some unique characteristics. Intriguingly, SmFeoA is found to adopt a unique dimer cross-linked by two zinc ions and six anions (chloride ions). Since FeoB has been found to contain a G-protein-like domain with low GTPase activity, FeoA may interact with FeoB through the SH3–G-protein domain interaction to act as a ferrous iron-transport activating factor.
doi:10.1107/S1744309110013941
PMCID: PMC2882759  PMID: 20516589
FeoA; ferrous iron transport; zinc binding; prokaryotic SH3 domain; Stenotrophomonus maltophilia
3.  Crystallization and preliminary X-ray diffraction characterization of RpfF, a key DSF synthase from Stenotrophomonas maltophilia  
Crystals of recombinant RpfF from S. maltophilia are tetragonal, space group P41212 or P43212, with unit-cell parameters a = 148.51, c = 122.82 Å, and diffract to 2.25 Å resolution.
Stenotrophomonas maltophilia has emerged as a critical nosocomial opportunistic pathogen in the last few years. It is resistant to many clinically useful antibiotics; hence, new ways of combatting this bacterium are essential. Diffusible signal factor (DSF) dependent quorum sensing is a major mechanism of virulence induction in S. maltophilia, with RpfF playing a key role in DSF biosynthesis. Inhibiting S. maltophilia RpfF (SmRpfF) function via small-molecule interference may constitute a new way of treating S. maltophilia infection. SmRpfF was therefore overexpressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. The crystals belonged to the tetragonal space group P41212 or P43212, with unit-cell parameters a = b = 148.51, c = 122.82 Å, and diffracted to a resolution of 2.25 Å.
doi:10.1107/S1744309109033156
PMCID: PMC2765891  PMID: 19851012
DFS synthase; RpfF; Stenotrophomonas maltophilia; structural genomics
4.  Crystallization and preliminary X-ray diffraction characterization of an essential protein from Xanthomonas campestris that contains a noncanonical PilZ signature motif yet is critical for pathogenicity 
An essential protein from the plant pathogen X. campestris pv. campestris (Xcc) that contains a noncanonical PilZ signature motif yet is critical for Xcc pathogenicity has been overexpressed in E. coli, purified and crystallized. The crystals diffracted to a resolution of 2.1 Å.
Recent studies have identified c-di-GMP as a novel secondary messenger molecule that is heavily involved in regulating bacterial biofilm formation, motility, production of pathogenicity factors etc. PilZ domain-containing proteins have been suggested and subsequently proved to be the c-­di-GMP receptor. However, considering the diverse biological functions exhibited by c-­di-GMP, it may be that receptors other than the PilZ domain exist. An essential protein from the plant pathogen Xanthomonas campestris pv. campestris (Xcc) that contains a noncanonical PilZ signature motif yet is critical for Xcc pathogenicity has been cloned, purified and crystallized. Detailed characterization of this protein may reveal an alternative binding mode of c-di-GMP and allow a more thorough understanding of how c-di-GMP exhibits its diverse effects.
doi:10.1107/S1744309109036239
PMCID: PMC2765900  PMID: 19851021
c-di-GMP; PilZ; Xanthomonous campestris
5.  The crystallization of apo-form UMP kinase from Xanthomonas campestris is significantly improved in a strong magnetic field 
A bacterial UMP kinase from the plant pathogen X. campestris pathovar campestris has been overexpressed in E. coli, purified and crystallized in a strong magnetic field. The crystals diffracted to 2.35 Å.
Bacterial UMP kinases (UMPKs) are crucial enzymes that are responsible for microbial UTP biosynthesis. Interestingly, eukaryotic and prokaryotic cells use different enzymes for UMP-phosphorylation reactions. Prokaryotic UMPKs are thus believed to be potential targets for antimicrobial drug development. Here, the cloning, expression and crystallization of SeMet-substituted XC1936, a bacterial UMPK from Xanthomonas campestris pathovar campestris, are reported. The crystallization of the apo-form UMPK was found to be significantly improved in a strong magnetic field; the crystals diffracted to a resolution of 2.35 Å, a dramatic improvement over the original value of 3.6 Å. Preliminary structural analyses of apo-form XC1936 using crystals grown in a strong magnetic field clearly reveal well defined loop regions involved in substrate-analogue binding that were previously not visible. Crystallization in a strong magnetic field thus was found to be indispensable in determining the flexible region of the XC1936 UMPK structure.
doi:10.1107/S1744309107018787
PMCID: PMC2335002  PMID: 17565191
Xanthomonas campestris; UMPK; optimum solubility screening; crystallization in a magnetic field
6.  Preliminary X-ray analysis of XC5848, a hypothetical ORFan protein with an Sm-like motif from Xanthomonas campestris  
A conserved hypothetical protein Se-XC5848 from X. campestris pv. campestris has been overexpressed in E. coli, purified and crystallized. Crystals obtained from the purified recombinant protein diffracted to a resolution of 1.68 Å.
XC5848, a hypothetical protein from the pathogenic bacterium Xanthomonas campestris that causes black rot, has been chosen as a potential target for the discovery of novel folds. It is unique to the Xanthomonas genus and has significant sequence identity mainly to corresponding proteins from the Xanthomonas genus. In this paper, the cloning, overexpression, purification and crystallization of the XC5848 protein are reported. The XC5848 crystals diffracted to a resolution of at least 1.68 Å. They belong to the orthorhombic space group P212121, with unit-cell parameters a = 48.13, b = 51.62, c = 82.32 Å. Two molecules were found in each asymmetric unit. Preliminary structural studies nevertheless indicate that XC5848 belongs to the highly conserved Sm-like α-­β-­β-β-β fold. However, significant differences in sequence and structure were observed. It therefore represents a novel variant of the crucial Sm-like motif that is heavily involved in mRNA splicing and degradation.
doi:10.1107/S1744309106052730
PMCID: PMC2330107  PMID: 17183169
Xanthomonas campestris; structural genomics; conserved hypothetical proteins; ORFans; Sm-like motif
7.  Crystallization and preliminary X-ray analysis of XC1015, a histidine triad-like protein from Xanthomonas campestris  
A HIT-like protein from the plant pathogen X. campestris pathovar campestris has been overexpressed in E. coli, purified and crystallized. The crystals diffract to 1.3 Å.
Histidine-triad (HIT) proteins are a superfamily of nucleotide hydrolases and transferases that contain a conserved HϕHϕHϕϕ motif (where ϕ is a hydrophobic amino acid) and are found in a variety of organisms. In addition to binding to a variety of nucleotides, other biological functions of the HIT superfamily proteins have been discovered and HIT malfunction has been implicated in several human diseases. Structural studies of HIT superfamily proteins are thus of particular interest. In this manuscript, the cloning, expression, crystallization and preliminary X-ray analysis of XC1015, a HIT protein present in the plant pathogen Xanthomonas campestris pathovar campestris, are reported. The XC1015 crystals diffracted to a resolution of 1.3 Å. They are tetragonal and belong to space group P43212, with unit-cell parameters a = 40.52, b = 40.52, c = 126.89 Å.
doi:10.1107/S1744309106047580
PMCID: PMC2225368  PMID: 17142912
Xanthomonas campestris; structural genomics; histidine triad-like protein
8.  Cloning, crystallization and preliminary X-ray studies of XC2981 from Xanthomonas campestris, a putative CutA1 protein involved in copper-ion homeostasis 
A probable copper-ion tolerance protein from the plant pathogen X. campestris has been overexpressed in E. coli, purified and crystallized.
Divalent metal ions play key roles in all living organisms, serving as cofactors for many proteins involved in a variety of electron-transfer activities. However, copper ions are highly toxic when an excessive amount is accumulated in a cell. CutA1 is a protein found in all kingdoms of life that is believed to participate in copper-ion tolerance in Escherichia coli, although its specific function remains unknown. Several crystal structures of multimeric CutA1 with different rotation angles and degrees of interaction between trimer interfaces have been reported. Here, the cloning, expression, crystallization and preliminary X-ray analysis of XC2981, a possible CutA1 protein present in the plant pathogen Xanthomonas campestris, are reported. The XC2981 crystals diffracted to a resolution of 2.6 Å. They are cubic and belong to space group I23, with unit-cell parameters a = b = c = 130.73 Å.
doi:10.1107/S1744309106039832
PMCID: PMC2225225  PMID: 17077491
CutA1; copper homeostasis; Xanthomonas campestris; structural genomics
9.  The cloning, crystallization and preliminary X-ray analysis of XC2113, a YaeQ protein from Xanthomonas campestris  
A YaeQ protein from the plant pathogen X. campestris pv. campestris has been overexpressed in E. coli, purified and crystallized. The crystals diffracted well to a resolution of 1.28 Å.
Xanthomonas campestris is a Gram-negative bacterium that is phytopathogenic to cruciferous plants and causes worldwide agricultural loss. It is therefore important to identify potential pathogenic factors involved in this plant disease. Here, the cloning, expression, crystallization and preliminary X-­ray analysis of XC2113, a YaeQ protein possibly involved in the production of virulence factors in Xanthomonas campestris pathovar campestris, are reported. The XC2113 crystals diffracted well to a resolution of at least 1.28 Å. They are orthorhombic and belong to space group P212121, with unit-cell parameters a = 32.86, b = 62.69, c = 79.96 Å.
doi:10.1107/S1744309106038383
PMCID: PMC2225173  PMID: 17012809
YaeQ; haemolysin; virulence factor; Xanthomonas campestris; structural genomics
10.  Cloning, crystallization and preliminary X-ray study of XC1258, a CN-hydrolase superfamily protein from Xanthomonas campestris  
A CN-hydrolase superfamily protein from the plant pathogen X. campestris has been overexpressed in E. coli, purified and crystallized.
CN-hydrolase superfamily proteins are involved in a wide variety of non-peptide carbon–nitrogen hydrolysis reactions, producing some important natural products such as auxin, biotin, precursors of antibiotics etc. These reactions all involve attack on a cyano or carbonyl carbon by a conserved novel catalytic triad Glu-Lys-Cys through a thiol acylenzyme intermediate. However, classification into the CN-hydrolase superfamily based on sequence similarity alone is not straightforward and further structural data are necessary to improve this categorization. Here, the cloning, expression, crystallization and preliminary X-­ray analysis of XC1258, a CN-hydrolase superfamily protein from the plant pathogen Xanthomonas campestris (Xcc), are reported. The SeMet-substituted XC1258 crystals diffracted to a resolution of 1.73 Å. They are orthorhombic and belong to space group P21212, with unit-cell parameters a = 143.8, b = 154.63, c = 51.3 Å, respectively.
doi:10.1107/S1744309106035433
PMCID: PMC2225184  PMID: 17012795
CN hydrolase; nitrilase superfamily; Xanthomonas campestris; structural genomics
11.  Structure of XC6422 from Xanthomonas campestris at 1.6 Å resolution: a small serine α/β-hydrolase 
The crystal structure of a conserved hypothetical protein from X. campestris has been determined to a resolution of 1.6 Å. The determined X. campestris structure shows that it belongs to the superfamily of serine α/β hydrolase, with an extra strand preceding the first β-strand to lead to extensive subunit interactions in the crystal.
XC6422 is a conserved hypothetical protein from Xanthomonas campestris pathovar campestris (Xcc), a Gram-negative yellow-pigmented pathogenic bacterium that causes black rot, one of the major worldwide diseases of cruciferous crops. The protein consists of 220 amino acids and its structure has been determined to 1.6 Å resolution using the multi-wavelength anomalous dispersion (MAD) method. Although it has very low sequence identity to protein sequences in the PDB (less than 20%), the determined structure nevertheless shows that it belongs to the superfamily of serine α/β-hydrolases, with an active site that is fully accessible to solvent owing to the absence of a lid domain. Modelling studies with the serine esterase inhibitor E600 indicate that XC6422 adopts a conserved Ser-His-Asp catalytic triad common to this superfamily and has a preformed oxyanion hole for catalytic activation. These structural features suggest that XC6422 is most likely to be a hydrolase active on a soluble ester or a small lipid. An extra strand preceding the first β-strand in the canonical α/β-hydrolase fold leads to extensive subunit interactions between XC6422 monomers, which may explain why XC6422 crystals of good diffraction quality can grow to dimensions of up to 1.5 mm in a few days.
doi:10.1107/S1744309106016265
PMCID: PMC2243109  PMID: 16754966
α/β-hydrolases; Xanthomonas campestris; oxyanion hole; esterases; lipases; crystal contacts
12.  Purification, crystallization and preliminary X-ray crystallographic analysis of rice Bowman–Birk inhibitor from Oryza sativa  
Rice Bowman–Birk inhibitor was expressed and crystallized.
Bowman–Birk inhibitors (BBIs) are cysteine-rich proteins with inhibitory activity against proteases that are widely distributed in monocot and dicot species. The expression of rice BBI from Oryza sativa is up-regulated and induced by pathogens or insects during germination of rice seeds. The rice BBI (RBTI) of molecular weight 15 kDa has been crystallized using the hanging-drop vapour-diffusion method. According to the diffraction of rice BBI crystals at a resolution of 2.07 Å, the unit cell belongs to space group P212121, with unit-cell parameters a = 74.37, b = 96.69, c = 100.36 Å. Preliminary analysis indicates four BBI molecules in an asymmetric unit, with a solvent content of 58.29%.
doi:10.1107/S1744309106014795
PMCID: PMC2243081  PMID: 16754971
Bowman–Birk inhibitors; rice
13.  Structure of the MecI repressor from Staphylococcus aureus in complex with the cognate DNA operator of mec  
The up-and-down binding of dimeric MecI to mecA dyad DNA may account for the cooperative effect of the repressor.
The dimeric repressor MecI regulates the mecA gene that encodes the penicillin-binding protein PBP-2a in methicillin-resistant Staphylococcus aureus (MRSA). MecI is similar to BlaI, the repressor for the blaZ gene of β-lactamase. MecI and BlaI can bind to both operator DNA sequences. The crystal structure of MecI in complex with the 32 base-pair cognate DNA of mec was determined to 3.8 Å resolution. MecI is a homodimer and each monomer consists of a compact N-­terminal winged-helix domain, which binds to DNA, and a loosely packed C-­terminal helical domain, which intertwines with its counter-monomer. The crystal contains horizontal layers of virtual DNA double helices extending in three directions, which are separated by perpendicular DNA segments. Each DNA segment is bound to two MecI dimers. Similar to the BlaI–mec complex, but unlike the MecI–bla complex, the MecI repressors bind to both sides of the mec DNA dyad that contains four conserved sequences of TACA/TGTA. The results confirm the up-and-down binding to the mec operator, which may account for cooperative effect of the repressor.
doi:10.1107/S1744309106009742
PMCID: PMC2222568  PMID: 16582476
MecI repressor
14.  Cloning, purification, crystallization and preliminary X-ray crystallographic analysis of XC847, a 3′-5′ oligoribonuclease from Xanthomonas campestris  
A DEDDh-type 3′-5′ oligoribonuclease from the plant pathogen X. campestris pv. campestris has been overexpressed in E. coli, purified and crystallized. The crystals diffracted to 2.1 Å with good quality.
Oligoribonucleases are essential components of RNA and DNA metabolism and close homologues of genes encoding them are found not only in prokaryotes but also in a wide range of eukaryotes, including yeast and humans. Inactivation of the oligoribonuclease gene (orn) can result in cellular lethality. Despite their important biological function, they have been studied little from a structural point of view. In this report, the cloning, expression, crystallization and preliminary X-ray analysis of XC847, a DEDDh-type 3′-5′ oligoribonuclease from the plant pathogen Xanthomonas campestris pv. campestris, a Gram-negative bacterium causing major worldwide disease of cruciferous crops, is described. The XC847 crystals diffracted to a resolution of at least 2.1 Å. They are tetragonal and belong to space group P43212, with unit-cell parameters a = b = 67.5, c = 89.8 Å. One molecule is present per asymmetric unit.
doi:10.1107/S1744309105027132
PMCID: PMC1991326  PMID: 16511191
3′-5′ oligoribonucleases; Orn; DEDDh; Xanthomonas campestris
15.  Preparation, crystallization and preliminary X-ray characterization of a conserved hypothetical protein XC1692 from Xanthomonas campestris  
A conserved hypothetical protein XC1692 from X. campestris pv. campestris has been overexpressed in E. coli. The purified recombinant protein crystallized in a variety of forms and diffracted to a resolution of at least 1.45 Å.
Xanthomonas campestris pv. campestris strain 17 is a Gram-negative yellow-pigmented pathogenic bacterium that causes black rot, one of the major worldwide diseases of cruciferous crops. Its genome contains approximately 4500 genes, one third of which have no known structure and/or function yet are highly conserved among several different bacterial genuses. One of these gene products is XC1692 protein, containing 141 amino acids. It was overexpressed in Escherichia coli, purified and crystallized in a variety of forms using the hanging-drop vapour-diffusion method. The crystals diffract to at least 1.45 Å resolution. They are hexagonal and belong to space group P63, with unit-cell parameters a = b = 56.9, c = 71.0 Å. They contain one molecule per asymmetric unit.
doi:10.1107/S1744309105018798
PMCID: PMC1952469  PMID: 16511130
Xanthomonas campestris; structural genomics; conserved hypothetical proteins
16.  A putative polyketide-synthesis protein XC5357 from Xanthomonas campestris: heterologous expression, crystallization and preliminary X-ray analysis 
A putative polyketide-synthesis protein XC5357 from X. campestris pv. campestris has been overexpressed in E. coli, purified and crystallized. The crystals diffracted to a resolution of at least 1.85 Å.
Xanthomonas campestris pv. campestris (Xcc) is a Gram-negative yellow-pigmented bacterium and is the causative agent of black rot, one of the major worldwide diseases of cruciferous crops. It also synthesizes a variety of polyketide metabolites that lead to important antibiotics. XC5357 is a putative 12.2 kDa protein of unknown structure from Xcc that is likely to be essential for polyketide synthesis. It was overexpressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. The crystals belong to the triclinic space group P1, with unit-cell parameters a = 43.7, b = 43.7, c = 46.5 Å, α = 65.0, β = 64.9, γ = 73.4°, and diffracted to a resolution of 1.85 Å.
doi:10.1107/S1744309105018968
PMCID: PMC1952467  PMID: 16511132
PKS; TcmJ; Xanthomonas campestris; structural genomics
17.  Cloning, purification crystallization and preliminary X-ray characterization of a conserved hypothetical protein XC6422 from Xanthomonas campestris  
A conserved hypothetical protein XC6422 from X. campestris pv. campestris has been overexpressed in E. coli, purified and crystallized. Crystals obtained from the purified recombinant protein showed a variety of forms that diffracted to at least 1.6 Å resolution.
Xanthomonas campestris pv. campestris is a Gram-negative yellow-pigmented pathogenic bacterium that causes black rot, one of the major worldwide diseases of cruciferous crops. Its genome contains approximately 4500 genes, roughly one third of which have no known structure and/or function. However, some genes of unknown function are highly conserved among several different bacterial genuses. XC6422 is one such conserved hypothetical protein and has been overexpressed in Escherichia coli, purified and crystallized in a variety of forms using the hanging-drop vapour-diffusion method. Crystals grew to approximately 2 × 1.5 × 0.4 mm in size after one week and diffracted to at least 1.6 Å resolution. They belong to the monoclinic space group C2, with one molecule per asymmetric unit and unit-cell parameters a = 75.8, b = 79.3, c = 38.2 Å, β = 109.4°. Determination of this structure may provide insights into the protein’s function.
doi:10.1107/S1744309105019391
PMCID: PMC1952462  PMID: 16511134
conserved hypothetical proteins; Xanthomonas campestris; structural genomics
18.  Cloning, purification, crystallization and preliminary X-ray analysis of XC229, a conserved hypothetical protein from Xanthomonas campestris  
A conserved hypothetical protein XC229 from X. campestris pv. campestris has been overexpressed in E. coli, purified and crystallized. A crystal of the purified recombinant protein diffracted to a resolution of 1.80 Å.
Xanthomonas campestris pv. campestris is a Gram-negative yellow-pigmented pathogenic bacterium that causes black rot, one of the major worldwide diseases of cruciferous crops. Its genome contains approximately 4500 genes, roughly one third of which have no known structure and/or function. However, some of these unknown genes are highly conserved among several different bacterial genuses. XC229 is one such protein containing 134 amino acids. It was overexpressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. The crystal diffracted to a resolution of at least 1.80 Å. It is cubic and belongs to space group I2x3, with unit-cell parameters a = b = c = 106.8 Å. It contains one or two molecules per asymmetric unit.
doi:10.1107/S1744309105018944
PMCID: PMC1952452  PMID: 16511131
Xanthomonas campestris; structural genomics; conserved hypothetical protein
19.  Preparation, crystallization and preliminary X-ray analysis of XC2382, an ApaG protein of unknown structure from Xanthomonas campestris  
A putative ApaG gene product from X. campestris pv. campestris was overexpressed in E. coli, purified and crystallized. The crystals diffracted to a resolution of at least 2.3 Å.
Xanthomonas campestris pv. campestris is the causative agent of black rot, one of the major worldwide diseases of cruciferous crops. Its genome encodes approximately 4500 proteins, roughly one third of which have unknown function. XC2382 is one such protein, with a MW of 14.2 kDa. Based on a bioinformatics study, it was annotated as an ApaG gene product that serves multiple functions. The ApaG protein has been overexpressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. The crystals diffracted to a resolution of at least 2.30 Å. They are tetragonal and belong to space group P41/3, with unit-cell parameters a = b = 57.6, c = 122.9 Å. There are two, three or four molecules in the asymmetric unit.
doi:10.1107/S1744309105018956
PMCID: PMC1952450  PMID: 16511133
ApaG; Xanthomonas campestris; structural genomics
20.  Cloning, expression, crystallization and preliminary X-ray analysis of a putative multiple antibiotic resistance repressor protein (MarR) from Xanthomonas campestris  
A putative repressor for the multiple antibiotic resistance operon from a plant pathogen X. campestris pv. campestris has been overexpressed in E. coli, purified and crystallized. The crystals diffracted to 2.3 Å with good quality.
The multiple antibiotic resistance operon (marRAB) is a member of the multidrug-resistance system. When induced, this operon enhances resistance of bacteria to a variety of medically important antibiotics, causing a serious global health problem. MarR is a marR-encoded protein that represses the transcription of the marRAB operon. Through binding with salicylate and certain antibiotics, however, MarR can derepress and activate the marRAB operon. In this report, the cloning, expression, crystallization and preliminary X-­ray analysis of XC1739, a putative MarR repressor protein present in the Xanthomonas campestris pv. campestris, a Gram-negative bacterium causing major worldwide disease of cruciferous crops, are described. The XC1739 crystals diffracted to a resolution of at least 1.8 Å. They are orthorhombic and belong to space group P212121, with unit-cell parameters a = 39.5, b = 54.2 and c = 139.5 Å, respectively. They contain two molecules in the asymmetric unit from calculation of the self-rotation function.
doi:10.1107/S1744309105019548
PMCID: PMC1952447  PMID: 16511135
MarR; antibiotic resistance repressor; transcriptional regulator; Xanthomonas campestris; structural genomics

Results 1-20 (20)