1gsq

THREE-DIMENSIONAL STRUCTURE, CATALYTIC PROPERTIES AND EVOLUTION OF A SIGMA CLASS GLUTATHIONE TRANSFERASE FROM SQUID, A PROGENITOR OF THE LENS-CRYSTALLINS OF CEPHALOPODSTHREE-DIMENSIONAL STRUCTURE, CATALYTIC PROPERTIES AND EVOLUTION OF A SIGMA CLASS GLUTATHIONE TRANSFERASE FROM SQUID, A PROGENITOR OF THE LENS-CRYSTALLINS OF CEPHALOPODS

Structural highlights 1gsq is a 1 chain structure with sequence from Todarodes pacificus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: Gene: CDNA INSERT OF CLONE PGST5 (Todarodes pacificus) Activity: Glutathione transferase, with EC number 2.5.1.18 Resources: FirstGlance, OCA, RCSB, PDBsum 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 The glutathione transferase from squid digestive gland is unique in its very high catalytic activity toward 1-chloro-2,4-dinitrobenzene and in its ancestral relationship to the genes encoding the S-crystallins of the lens of cephalopod eye. The three-dimensional structure of this glutathione transferase in complex with the product 1-(S-glutathionyl)-2,4-dinitrobenzene (GSDNB) has been solved by multiple isomorphous replacement techniques at a resolution of 2.4 A. Like the cytosolic enzymes from vertebrates, the squid protein is a dimer. The structure is similar in overall topology to the vertebrate enzymes but has a dimer interface that is unique when compared to all of the vertebrate and invertebrate structures thus far reported. The active site of the enzyme is very open, a fact that appears to correlate with the high turnover number (800 s-1 at pH 6.5) toward 1-chloro-2,4-dinitrobenzene. Both kcat and kcat/KmCDNB exhibit pH dependencies consistent with a pKa for the thiol of enzyme-bound GSH of 6.3. The enzyme is not very efficient at catalyzing the addition of GSH to enones and epoxides. This particular characteristic appears to be due to the lack of an electrophilic residue at position 106, which is often found in other GSH transferases. The F106Y mutant enzyme is much improved in catalyzing these reactions. Comparisons of the primary structure, gene structure, and three-dimensional structure with class alpha, mu, and pi enzymes support placing the squid protein in a separate enzyme class, sigma. The unique dimer interface suggests that the class sigma enzyme diverged from the ancestral precursor prior to the divergence of the precursor gene for the alpha, mu, and pi classes. Three-dimensional structure, catalytic properties, and evolution of a sigma class glutathione transferase from squid, a progenitor of the lens S-crystallins of cephalopods.,Ji X, von Rosenvinge EC, Johnson WW, Tomarev SI, Piatigorsky J, Armstrong RN, Gilliland GL Biochemistry. 1995 Apr 25;34(16):5317-28. PMID:7727393 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Glutathione S-transferase

spinqualitylabelsall models 1gsq, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image