5f8v

Crystal structure of PLP bound phosphoserine aminotransferase (PSAT) from Trichomonas vaginalis

spinqualitylabelsall models 5f8v, resolution 2.14Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5f8v is a 8 chain structure with sequence from Trichomonas vaginalis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.14Å Ligands: LLP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A2DW27_TRIV3 Publication Abstract from PubMed BACKGROUND: Phosphoserine aminotransferase (PSAT) catalyses the second reversible step of the phosphoserine biosynthetic pathway in Trichomonas vaginalis, which is crucial for the synthesis of serine and cysteine. METHODS: PSAT from T. vaginalis (TvPSAT) was analysed using X-ray crystallography, enzyme kinetics, and molecular dynamics simulations. RESULTS: The crystal structure of TvPSAT was determined to 2.15A resolution, and is the first protozoan PSAT structure to be reported. The active site of TvPSAT structure was found to be in a closed conformation, and at the active site PLP formed an internal aldimine linkage to Lys 202. In TvPSAT, Val 340 near the active site while it is Arg in most other members of the PSAT family, might be responsible in closing the active site. Kinetic studies yielded Km values of 54 muM and 202 muM for TvPSAT with OPLS and AKG, respectively. Only iodine inhibited the TvPSAT activity while smaller halides could not inhibit. CONCLUSION: Results from the structure, comparative molecular dynamics simulations, and the inhibition studies suggest that iodine is the only halide that can bind TvPSAT strongly and may thus inhibit the activity of TvPSAT. The long loop between beta8 and alpha8 at the opening of the TvPSAT active site cleft compared to other PSATs, suggests that this loop may help control the access of substrates to the TvPSAT active site and thus influences the enzyme kinetics. GENERAL SIGNIFICANCE: Our structural and functional studies have improved our understanding of how PSAT helps this organism persists in the environment. Structural investigation and inhibitory response of halide on phosphoserine aminotransferase from Trichomonas vaginalis.,Singh RK, Mazumder M, Sharma B, Gourinath S Biochim Biophys Acta. 2016 Jul;1860(7):1508-18. doi:, 10.1016/j.bbagen.2016.04.013. Epub 2016 Apr 19. PMID:27102280 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Aminotransferase 3D structures

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