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Genome‐wide analysis of integral membrane proteins from eubacterial, archaean, and eukaryotic organisms
Author(s) -
Wallin Erik,
Heijne Gunnar Von
Publication year - 1998
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560070420
Subject(s) - methanococcus , transmembrane protein , biology , membrane protein , integral membrane protein , genome , transmembrane domain , caenorhabditis elegans , genetics , biochemistry , microbiology and biotechnology , archaea , gene , membrane , receptor
We have carried out detailed statistical analyses of integral membrane proteins of the helix‐bundle class from eubacterial, archaean, and eukaryotic organisms for which genome‐wide sequence data are available. Twenty to 30% of all ORFs are predicted to encode membrane proteins, with the larger genomes containing a higher fraction than the smaller ones. Although there is a general tendency that proteins with a smaller number of transmembrane segments are more prevalent than those with many, uni‐cellular organisms appear to prefer proteins with 6 and 12 transmembrane segments, whereas Caenorhabditis elegans and Homo sapiens have a slight preference for proteins with seven transmembrane segments. In all organisms, there is a tendency that membrane proteins either have manytransmembrane segments with short connecting loops or few transmembrane segments with large extra‐membraneous domains. Membrane proteins from all organisms studied, except possibly the archaeon Methanococcus jannaschii , follow the so‐called “positive‐inside” rule; i.e., they tend to have a higher frequency of positively charged residues in cytoplasmic than in extra‐cytoplasmic segments.