Lipopolysaccharide is an essential component of the outer membrane of Gram-negative bacteria and consists of three elements: lipid A, the core oligosaccharide and the O-antigen. The inner core region is highly conserved and contains at least one residue of 3-deoxy-D-manno-octulosonate (Kdo). The first committed step of Kdo biosynthesis is the aldol-keto isomerisation of d-ribulose 5-phosphate to d-arabinose 5-phosphate catalyzed by arabinose 5-phosphate isomerase encoded in Escherichia coli by the kdsD gene. KdsD contains an N-terminal sugar isomerase (SIS) domain commonly found in phosphosugar isomerases but its three-dimensional structure is unknown. The structure of the KdsD SIS domain has been predicted by homology modeling using the hypothetical 3etn protein as a template. Moreover by sequence alignments, comparison with other sugar isomerases structurally related to KdsD, and site-directed mutagenesis we implicated four residues in KdsD activity or substrate recognition. A possible role of these residues in the catalysis is discussed.

Structure prediction and functional analysis of KdsD, an enzyme involved in lipopolysaccharide biosynthesis / S. Sommaruga, L.D. Gioia, P. Tortora, A. Polissi. - In: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS. - ISSN 0006-291X. - 388:2(2009 Oct 16), pp. 222-227.

Structure prediction and functional analysis of KdsD, an enzyme involved in lipopolysaccharide biosynthesis

S. Sommaruga;A. Polissi
2009-10-16

Abstract

Lipopolysaccharide is an essential component of the outer membrane of Gram-negative bacteria and consists of three elements: lipid A, the core oligosaccharide and the O-antigen. The inner core region is highly conserved and contains at least one residue of 3-deoxy-D-manno-octulosonate (Kdo). The first committed step of Kdo biosynthesis is the aldol-keto isomerisation of d-ribulose 5-phosphate to d-arabinose 5-phosphate catalyzed by arabinose 5-phosphate isomerase encoded in Escherichia coli by the kdsD gene. KdsD contains an N-terminal sugar isomerase (SIS) domain commonly found in phosphosugar isomerases but its three-dimensional structure is unknown. The structure of the KdsD SIS domain has been predicted by homology modeling using the hypothetical 3etn protein as a template. Moreover by sequence alignments, comparison with other sugar isomerases structurally related to KdsD, and site-directed mutagenesis we implicated four residues in KdsD activity or substrate recognition. A possible role of these residues in the catalysis is discussed.
Aldose-Ketose Isomerases; Amino Acid Sequence; Escherichia coli Proteins; Histidine; Lipopolysaccharides; Lysine; Molecular Sequence Data; Mutation; Protein Conformation; Protein Structure, Tertiary; Sequence Alignment; Sugar Acids
Settore BIO/19 - Microbiologia Generale
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/611251
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