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G D Brayer

Publications and source records attributed to G D Brayer.

77 records · Page 5Linked to original sources
PubMed1979

Crystallographic and kinetic investigations of the covalent complex formed by a specific tetrapeptide aldehyde and the serine protease from Streptomyces griseus.

X-ray crystallographic data show that a specific tetrapeptide aldehyde inhibitor (N-acetylprolylalanylprolylphenylalaninal) forms a stable, covalent, tetrahedral addition complex with the serine protease, SGPA, from Streptomyces griseus. Earlier proposals, based on kinetic measurements, for the covalent nature of such linkages are confirmed, and the difference electron density map of this aldehyde inhibitor indicates that a major conformational change of the histidyl-57 side chain occurs on inhibitor binding.

Aldehydes↗
PubMed1979

The 2.8 A resolution structure of Streptomyces griseus protease B and its homology with alpha-chymotrypsin and Streptomyces griseus protease A.

The 2.8 A (1 A = 0.1 nm) resolution structure of the crystalline orthorhombic form of the microbial serine protease Streptomyces griseus protease B (SGPB) has been solved by the method of multiple isomorphous replacement using five heavy-atom derivatives. The geometrical arrangement of the active site quartet, Ser-214, Asp-102, His-57, and Ser-195, is similar to that found for pancreatic alpha-chymotrypsin. SGPB and alpha-chymotrypsin have only 18% identity of primary structure but their tertiary structures are 63% topologically equivalent within a root mean square deviation of 2.07 A. The major tertiary structural differences between the bacterial enzyme SGPB and the pancreatic enzymes is due to the zymogen requirement of the multicellular organisms in order to protect themselves against autolytic degradation. The two pronase enzymes, SGPB and Streptomyces griseus protease A (SGPA), have 61% identity of sequence and their tertiary structures are 85% topologically equivalent within a root mean square deviation of 1.46 A. The active site regions of SGPA and SGPB are similar and their tertiary structures differ only in three minor regions of surface loops.

Amino Acid Sequence↗
PubMed1978

Amino acid sequence alignment of bacterial and mammalian pancreatic serine proteases based on topological equivalences.

The three-dimensional structures of the bacterial serine proteases SGPA, SGPB, and alpha-lytic protease have been compared with those of the pancreatic enzymes alpha-chymotrypsin and elastase. This comparison shows that approximately 60% (55-64%) of the alpha-carbon atom positions of the bacterial serine proteases are topologically equivalent to the alpha-carbon atom positions of the pancreatic enzymes. The corresponding value for a comparison of the bacterial enzymes among themselves is approximately 84%. The results of these topological comparisons have been used to deduce an experimentally sound sequence alignment for these several enzymes. This alignment shows that there is extensive tertiary structural homology among the bacteria and pancreatic enzymes without significant primary sequence identity (less than 21%). The acquisition of a zymogen function by the pancreatic enzymes is accompanied by two major changes to the bacterial enzymes' architecture: an insertion of 9 residues to increase the length of the N-terminal loop, and one of 12 residues to a loop near the activation salt bridge. In addition, in these two enzyme families, the methionine loop (residues 164-182) adopts very different comformations which are associated with their altered substrate specificities.

Amino Acid Sequence↗