RRC ID 54565
Author Zhang Z, Shimizu Y, Kawarabayasi Y.
Title Characterization of the amino acid residues mediating the unique amino-sugar-1-phosphate acetyltransferase activity of the archaeal ST0452 protein.
Journal Extremophiles
Abstract The ST0452 protein from the thermophilic archaean Sulfolobus tokodaii has been identified as an enzyme with multiple sugar-1-phosphate nucleotidylyltransferase and amino-sugar-1-phosphate acetyltransferase (amino-sugar-1-P AcTase) activities. Analysis of the protein showed that in addition to glucosamine-1-phosphate (GlcN-1-P) AcTase activity, it possesses unique galactosamine-1-phosphate (GalN-1-P) AcTase activity not detected in any other proteins. Comparison of the crystal structures of the ST0452 protein and GlmU from Escherichia coli (EcGlmU), which possesses only GlcN-1-P AcTase activity, showed that the overall sequence identity between these two proteins is less than 25 %, but the amino acid residues predicted to comprise the catalytic center of EcGlmU are conserved in the ST0452 protein. To understand the molecular mechanism by which the ST0452 amino-sugar-1-P AcTase activity recognizes two independent substrates, several ST0452 substitution and truncation mutant proteins were constructed and analyzed. We found that His308 is essential for both GalN-1-P and GlcN-1-P AcTase activities, whereas Tyr311 and Asn331 are important only for the GalN-1-P AcTase activity. In addition, deletion of the C-terminal 5 or 11 residues showed that the 11-residue C-terminal region exerts a modest stimulatory effect on GalN-1-P AcTase activity but dramatically suppresses GlcN-1-P AcTase activity. This region also appears to make an important contribution to the thermostability of the entire ST0452 protein. Systematic deletions from the C-terminus also demonstrated that the C-terminal region with the β-helix structure has an important role mediating the trimerization of the ST0452 protein. This is the first report of an analysis of a thermostable archaeal enzyme exhibiting multiple amino-sugar-1-P AcTase activities.
Volume 19(2)
Pages 417-27
Published 2015-3-1
DOI 10.1007/s00792-014-0727-9
PMID 25567746
MeSH Amino Acid Sequence Archaeal Proteins / chemistry* Archaeal Proteins / genetics Archaeal Proteins / metabolism Escherichia coli Proteins / chemistry Galactosamine / analogs & derivatives* Galactosamine / metabolism Galactosephosphates / metabolism* Glucosamine 6-Phosphate N-Acetyltransferase / chemistry* Glucosamine 6-Phosphate N-Acetyltransferase / genetics Glucosamine 6-Phosphate N-Acetyltransferase / metabolism Molecular Sequence Data Multienzyme Complexes / chemistry Protein Binding Protein Structure, Tertiary Sulfolobus / enzymology*
IF 2.462
Times Cited 4
DNA material Thermophile Gene Expression Plasmid (RDB15969)