Distinguishing features of delta-proteobacterial genomes.
We analyzed several features of five currently available delta-proteobacterial genomes, including two aerobic bacteria exhibiting predatory behavior and three anaerobic sulfate-reducing bacteria. The delta genomes are distinguished from other bacteria by several properties: (i) The delta genomes contain two "giant" S1 ribosomal protein genes in contrast to all other bacterial types, which encode a single or no S1; (ii) in most delta-proteobacterial genomes the major ribosomal protein (RP) gene cluster is near the replication terminus whereas most bacterial genomes place the major RP cluster near the origin of replication; (iii) the delta genomes possess the rare combination of discriminating asparaginyl and glutaminyl tRNA synthetase (AARS) together with the amido-transferase complex (Gat CAB) genes that modify Asp-tRNA(Asn) into Asn-tRNA(Asn) and Glu-tRNA(Gln) into Gln-tRNA(Gln); (iv) the TonB receptors and ferric siderophore receptors that facilitate uptake and removal of complex metals are common among delta genomes; (v) the anaerobic delta genomes encode multiple copies of the anaerobic detoxification protein rubrerythrin that can neutralize hydrogen peroxide; and (vi) sigma(54) activators play a more important role in the delta genomes than in other bacteria. delta genomes have a plethora of enhancer binding proteins that respond to environmental and intracellular cues, often as part of two-component systems; (vii) delta genomes encode multiple copies of metallo-beta-lactamase enzymes; (viii) a host of secretion proteins emphasizing SecA, SecB, and SecY may be especially useful in the predatory activities of Myxococcus xanthus; (ix) delta proteobacteria drive many multiprotein machines in their periplasms and outer membrane, including chaperone-feeding machines, jets for slime secretion, and type IV pili. Bdellovibrio replicates in the periplasm of prey cells. The sulfate-reducing delta proteobacteria metabolize hydrogen and generate a proton gradient by electron transport. The predicted highly expressed genes from delta genomes reflect their different ecologies, metabolic strategies, and adaptations.
Karlin
Samuel
S
Department of Mathematics, Stanford University, Stanford, CA 94305, USA. karlin@math.stanford.edu
Brocchieri
Luciano
L
Mrázek
Jan
J
Kaiser
Dale
D
D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics*; D001501:Bdellovibrio / Q000378:metabolism; D020564:Deltaproteobacteria / Q000235:genetics*; D004734:Energy Metabolism; D016680:Genome, Bacterial; D006019:Glycolysis; D008957:Models, Genetic; D015233:Models, Statistical; D008969:Molecular Sequence Data; D005810:Multigene Family; D011522:Protons; D012269:Ribosomal Proteins / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D014233:Tricarboxylic Acids / Q000378:metabolism
D011522:Protons; D012269:Ribosomal Proteins; D014233:Tricarboxylic Acids; C015494:ribosomal protein S1; D000604:Amino Acyl-tRNA Synthetases