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OJB©
Online Journal of Bioinformatics©
Volume
6 (2):74-90, 2005
In silico identification and modelling of a putative
iron-regulated TonB-dependant outer membrane
receptor
protein from the genome of Leptospira interrogans serovar Lai
Sritharan M, Ramadevi S, Pasupala N, Asuthkar S, Tajne S
Department of Animal Sciences,
Sritharan M, Ramadevi S, Pasupala N, Asuthkar S,
Tajne S. In silico
identification and modelling of a putative
iron-regulated TonB-dependant outer membrane receptor
protein from the genome of Leptospira interrogans Serovar Lai, Online
J Bioinformatics 6 (2) : 74-90, 2005. Identification and modelling
of a leptospiral TonB-dependant
outer membrane protein homologous to Fe3+-enterobactin receptor FepA of Escherichia
coli is described. This protein LEP_IRMP (leptospiral
iron-regulated membrane protein), has a fold of 3 domains: the
β-barrel, plug domain and N-terminal TonB box, characteristic of bacterial outer
membrane receptors involved in the transport of iron. The Fur box was
identified upstream of the lep_irmp gene
encoding this protein, implying the possible regulation of its expression by
iron. Also, the genes for the Fur regulator and heme oxygenase are found as neighbourhood genes. The FRAP-NPNL
motif involved in heme binding is present in
LEP_IRMP. Using sequence-specific primers, the full-length lep_irmp gene in several pathogenic Leptospira sp. and absence in non-pathogenic leptospires has
been identified. The possible role of the protein in heme
binding by pathogenic leptospires is discussed in the
light of the above observations as
well as the failure to detect siderophores under
conditions of iron deprivation.
KEY WORDS: iron, TonB-dependant outer membrane protein,
LEP_IRMP, Leptospira, plug domain, β-barrel domain,
N-terminal TonB box, heme
binding.