3ci7

Crystal structure of a simplified BPTI containing 20 alanines

spinqualitylabelsall models 3ci7, resolution 1.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ci7 is a 4 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.4Å Ligands: SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed We report the high-resolution crystal structures of an extensively simplified variant of bovine pancreatic trypsin inhibitor containing 20 alanines (BPTI-20st) and a reference single-disulfide-bonded variant (BPTI-[5,55]st) at, respectively, 1.39 and 1.09 A resolutions. The sequence was simplified based on the results of an alanine scanning experiment, as reported previously. The effects of the multiple alanine substitutions on the overall backbone structure were surprisingly small (C(alpha) atom RMSD of 0.53 A) being limited to small local structural perturbations. Both BPTI variants retained a wild-type level of trypsin inhibitory activity. The side-chain configurations of residues buried in the hydrophobic cores (<30% accessible surface area) were almost perfectly retained in both BPTI-20st and BPTI-[5,55]st, indicating that neither multiple alanine replacements nor the removal of the disulfide bonds affected their precise placements. However, the side chains of three partially buried residues (Q31, R20, and to some extent Y21) and several unburied residues rearranged into alternative dense-packing structures, suggesting some plasticity in their shape complementarity. These results indicate that a protein sequence simplified over its entire length can retain its densely packed, native side-chain structure, and suggest that both the design and fold recognition of natively folded proteins may be easier than previously thought. Crystal structure of an extensively simplified variant of bovine pancreatic trypsin inhibitor in which over one-third of the residues are alanines.,Islam MM, Sohya S, Noguchi K, Yohda M, Kuroda Y Proc Natl Acad Sci U S A. 2008 Oct 7;105(40):15334-9. Epub 2008 Sep 30. PMID:18829434 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also BPTI 3D structures

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