Omp85 from the Thermophilic Cyanobacterium Thermosynechococcus elongatus Differs from Proteobacterial Omp85 in Structure and Domain Composition

• DOI: 10.1074/jbc.m110.112516
• Publication Date: 2010-03-30T02:24:30Z
• Authors: Thomas Arnold; Kornelius Zeth; Dirk Linke
• Keywords: Porin

Omp85 proteins are essential located in the bacterial outer membrane. They involved membrane biogenesis and assist protein insertion folding by an unknown mechanism. Homologous exist eukaryotes, where they mediate assembly organelles of endosymbiotic origin, mitochondria chloroplasts. We set out to explore homologous relationship between cyanobacteria chloroplasts, studying from thermophilic cyanobacterium Thermosynechococcus elongatus. Using state-of-the art sequence analysis clustering methods, we show how this is more closely related its chloroplast homologue Toc75 than proteobacterial Omp85, a finding supported single channel conductance measurements. have solved structure periplasmic part 1.97 A resolution, demonstrate that contrast Escherichia coli has only three, not five, polypeptide transport-associated (POTRA) domains, which recognize substrates generally interact with other bigger complexes. model these POTRA domains attached membrane, based on two-partner secretion system proteins, analyze. Finally, discuss different numbers evolved, evolve day, accomplish increasing number interactions helper proteins.