title: Overexpression, purification, crystallization and structure determination of AspB, a putative aspartate aminotransferase from Mycobacterium tuberculosis.
abstract: A recombinant version of a putative aspartate aminotransferase, AspB (encoded by the ORF Rv3565), from Mycobacterium tuberculosis (Mtb) was overexpressed in M. smegmatis and purified to homogeneity using liquid chromatography. Crystals of AspB were grown in a condition consisting of 0.2 M ammonium phosphate monobasic, 0.1 M calcium chloride dihydrate employing the hanging-drop vapour-diffusion method at 298 K. The crystals diffracted to a limit of 2.50 Å resolution and belonged to the orthorhombic space group P2₁2₁2₁, with unit-cell parameters a=93.27, b=98.19, c=198.70 Å. The structure of AspB was solved by the molecular-replacement method using a putative aminotransferase from Silicibacter pomeroyi (PDB entry 3h14) as the search model. The template shares 46% amino-acid sequence identity with Mtb AspB. The crystal asymmetric unit contains four AspB molecules (the Mr of each is 42,035 Da).
authors.affiliation: Protein Crystallography Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors.forename: Deepak Chandra
authors.initials: DC
authors.lastname: Saroj
authors.affiliation: Protein Crystallography Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors.forename: Khundrakpam Herojit
authors.initials: KH
authors.lastname: Singh
authors.affiliation: Protein Crystallography Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors.forename: Avishek
authors.initials: A
authors.lastname: Anant
authors.affiliation: Protein Crystallography Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors.forename: Bichitra K
authors.initials: BK
authors.lastname: Biswal
mesh_terms: D000595:Amino Acid Sequence; D001219:Aspartate Aminotransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D008969:Molecular Sequence Data; D020102:Mycobacterium smegmatis / Q000235:genetics / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000737:chemistry* / Q000201:enzymology; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D040681:Structural Homology, Protein
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D001219:Aspartate Aminotransferases
keywords: AspB; Mycobacterium tuberculosis