Affiliations: G.N. Ramachandran Knowledge Centre for Genome
Informatics, Institute of Genomics and Integrative Biology, Mall Road, Delhi
110 007, India Tel: +91 11 2766 6156, x169; +91 11 2766 6157, x169, Fax: +91 11
2766 7471 | School of Biotechnology, Guru Govind Singh
Indraparastha University, Kashmere Gate, Delhi 110 006, India E-mail:
[email protected]; [email protected]
Note: [] Corresponding author
Abstract: The number and functions of the low complexity (LC) proteins from
four enteric bacterial pathogens Escherichia coli O157, Vibrio cholerae,
Helicobacter pylori and Campylobacter jejuni were compared. For this purpose
the LC proteins were grouped into 3 categories for pairwise comparisons. These
were COMMON, VARIANT and LC proteins with No Homologues (LCNH). Homologous LC
proteins in both species in a given pairwise comparison were grouped as COMMON.
LC Proteins of same function but not of low complexity in either of the species
in a given pair were grouped as VARIANT. LC proteins without any homologues in
either species were grouped as LCNH. Conservation patterns were inferred by
comparing them under 3 functional classes CELLULAR PROCESSES (CP), TRANSPORT
& MEMBRANE ASSOCIATED (TM) and CHARACTERISTIC (CH). In the COMMON category,
highest similarity was found between E. coli O157 and V. cholerae on the one
hand and H. pylori and C. jejuni on the other under the functional class CP.
This parallels taxonomic classification in that E. coli and V. cholerae are
classified under gamma subdivision of proteobacteria whereas H. pylori and C.
jejuni are classified under the epsilon subdivision. The data from LCNH group,
although more diffuse, was complementary the to pattern drawn from COMMON
category in that the numbers of LCNH in the pair {E. coli O157, V. cholerae}
and in {H. pylori, C. jejuni} were lowest. No consistent patterns were observed
in the VARIANT category. These observations indicate that although low
complexity segments are thought to undergo variations, species patterns do
exist in a limited set of low complexity proteins that parallels taxonomic
classification.
