4k1v | pdb_00004k1v

Crystal structure of delta5-3-ketosteroid isomerase containing Y16F and Y57F mutations

spinqualitylabelsall models 4k1v, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4k1v is a 1 chain structure with sequence from Pseudomonas putida. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 4k1u Gene: ksi (Pseudomonas putida) Activity: Steroid Delta-isomerase, with EC number 5.3.3.1 Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed Proteins have evolved to compensate for detrimental mutations. However, compensatory mechanisms for protein defects are not well understood. Using ketosteroid isomerase (KSI), we investigated how second-site mutations could recover defective mutant function and stability. Previous results revealed that the Y30F mutation rescued the Y14F, Y55F and Y14F/Y55F mutants by increasing the catalytic activity by 23-, 3- and 1.3-fold, respectively, and the Y55F mutant by increasing the stability by 3.3 kcal/mol. To better understand these observations, we systematically investigated detailed structural and thermodynamic effects of the Y30F mutation on these mutants. Crystal structures of the Y14F/Y30F and Y14F/Y55F mutants were solved at 2.0 and 1.8 previoulsy solved structures of wild-type and other mutant KSIs. Structural analyses revealed that the Y30F mutation partially restored the active-site cleft of these mutant KSIs. The Y30F mutation also increased Y14F and Y14F/Y55F mutant stability by 3.2 and 4.3 kcal/mol, respectively, and the melting temperatures of the Y14F, Y55F and Y14F/Y55F mutants by 6.4 degrees C, 5.1 degrees C and 10.0 degrees C, respectively. Compensatory effects of the Y30F mutation on stability might be due to improved hydrophobic interactions because removal of a hydroxyl group from Tyr30 induced local compaction by neighboring residue movement and enhanced interactions with surrounding hydrophobic residues in the active site. Taken together, our results suggest that perturbed active-site geometry recovery and favorable hydrophobic interactions mediate the role of Y30F as a secondsite suppressor. Rescue of deleterious mutations by the compensatory Y30F mutation in ketosteroid isomerase.,Cha HJ, Jang do S, Kim YG, Hong BH, Woo JS, Kim KT, Choi KY Mol Cells. 2013 Jul;36(1):39-46. doi: 10.1007/s10059-013-0013-1. Epub 2013 Jun 3. PMID:23740430 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ketosteroid Isomerase

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