Study on glucuronyltransferase activity of KfiA

2011 Fiscal Year Final Research Report

• Project/Area Number: 21570115
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Structural biochemistry
• Research Institution: Kyushu University
• Principal Investigator: YOSHIMITSU Kakuta 九州大学, 農学研究院, 准教授 (00314360)
• Project Period (FY): 2009 – 2011
• Keywords: ヘパロサン / 糖鎖生合成

Research Abstract

Heparan sulfate is a ubiquitous glycosaminoglycan in the extracellular matrix of most animals. It interacts with various molecules and exhibits important biological functions. K5 antigen produced by Escherichia coli strain K5 is a linear polysaccharide N-acetylheparosan consisting of GlcUA beta1-4 and GlcNAc alpha1-4 repeating disaccharide, which forms the backbone of heparan sulfate. Here, we expressed and purified the recombinant KfiA and KfiC proteins and then characterized these enzymes. Whereas the recombinant KfiC alone exhibited no GlcUA transferase activity, it did exhibit GlcUA transferase and polymerization activities in the presence of KfiA. In contrast, KfiA had GlcNAc transferase activity itself, which was unaffected by the presence of KfiC. The GlcNAc and GlcUA transferase activities were analyzed with various truncated and point mutants of KfiA and KfiC. The point mutants replacing aspartic acid of a DXD motif and lysine and glutamic acid of an ionic amino acid cluster, and the truncated mutants deleting the C-terminal and N-terminal sites, revealed the essential regions for GlcNAc and GlcUA transferase activity of KfiC and KfiA, respectively. The interaction of KfiC with KfiA is necessary for the GlcUA transferase activity of KfiC but not for the enzyme activity of KfiA. Together, these results indicate that the complex of KfiA and KfiC has polymerase activity to synthesize N-acetylheparosan, providing a useful tool toward bioengineering of defined heparan sulfate chains.

Research Products

• [Journal Article] Glucuronyltransferase activity of KfiC from Escherichia coli strain K5 requires association of KfiA: KfiC and KfiA are essential enzymes for production of K5 polysaccharide, N-acetylheparosan (2010)
  • Author(s): Sugiura N, Baba Y, Kawaguchi Y, Iwatani T, Suzuki K, Kusakabe T, Yamagishi K, Kimata K, Kakuta Y, Watanabe H., J Biol Chem.
  • Journal Title: J Biol Chem Volume: 285(3) Pages: 1597-1606