Cloning, sequencing, expression, and complementation analysis of the Escherichia coli K1 kps region 1 gene, kpsE, and identification of an upstream open reading frame encoding a protein with homology to GutQ.
The kps locus for polysialic acid capsule expression in Escherichia coli K1 is composed of a central group of biosynthetic neu genes, designated region 2, flanked on either side by region 1 or region 3 kps genes with poorly defined functions. Chromosomal mutagenesis with MudJ and subsequent complementation analysis, maxicell and in vitro protein expression studies, and nucleotide sequencing identified the region 1 gene, kpsE, which encodes a 39-kDa polypeptide. Polarity of the kpsE::lacZ mutation suggests an operonic structure for region 1. KpsE is homologous to putative polysaccharide-translocation components previously identified in Haemophilus influenzae type b and Neisseria meningitidis group B. An open reading frame upstream of kpsE encodes a 35-kDa polypeptide with homology to GutQ, a putative ATP-binding protein of unknown function encoded by gutQ of the glucitol utilization operon. Whether expression of the gutQ homolog as the potential first gene of region 1 is required for polysialic acid synthesis or localization is presently unknown.
Cieslewicz
M J
MJ
Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign 61801.
Steenbergen
S M
SM
Vimr
E R
ER
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015870:Gene Expression; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006193:Haemophilus influenzae / Q000235:genetics; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000235:genetics; D016366:Open Reading Frames; D009876:Operon; D014176:Protein Biosynthesis; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D013012:Sorbitol / Q000378:metabolism; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C084729:kpsE protein, E coli; C073627:srlQ protein, E coli; D013012:Sorbitol