1yjb
SUBTILISIN BPN' 8397+1 (E.C. 3.4.21.14) (MUTANT WITH MET 50 REPLACED BY PHE, ASN 76 REPLACED BY ASP, GLY 169 REPLACED BY ALA, GLN 206 REPLACED BY CYS, ASN 218 REPLACED BY SER AND LYS 256 REPLACED BY TYR) (M50F, N76D, G169A, Q206C, N218S, AND K256Y) IN 35% DIMETHYLFORMAMIDE
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OverviewOverview
The serine protease subtilisin BPN' is a useful catalyst for peptide, synthesis when dissolved in high concentrations of a water-miscible, organic co-solvent such as N,N-dimethylformamide (DMF). However, in 50%, DMF, the k(cat) for amide hydrolysis is two orders of magnitude lower than, in aqueous solution. Surprisingly, the k(cat) for ester hydrolysis is, unchanged in 50% DMF. To explain this alteration in activity, the, structure of subtilisin 8397+1 was determined in 20, 35, and 50% (v/v) DMF, to 1.8 A resolution. In 50% DMF, the imidazole ring of His64, the central, residue of the catalytic triad, has rotated approximately 180 degrees, around the Cbeta-Cgamma bond. Two new water molecules in the active site, stabilize the rotated conformation. This rotation places His64 in an, unfavorable geometry to interact with the other members of the catalytic, triad, Ser221 and Asp32. NMR experiments confirm that the characteristic, resonance due to the low barrier hydrogen bond between the His64 and Asp32, is absent in 50% DMF. These experiments provide a clear structural basis, for the change in activity of serine proteases in organic co-solvents.
About this StructureAbout this Structure
1YJB is a Single protein structure of sequence from Bacillus amyloliquefaciens with and as ligands. Active as Transferred entry: 3.4.21.62, with EC number 3.4.21.14 Known structural/functional Sites: , and . Full crystallographic information is available from OCA.
ReferenceReference
Breaking the low barrier hydrogen bond in a serine protease., Kidd RD, Sears P, Huang DH, Witte K, Wong CH, Farber GK, Protein Sci. 1999 Feb;8(2):410-7. PMID:10048334
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