3DZM

Crystal structure of a major outer membrane protein from Thermus thermophilus HB27

Summary for 3DZM

• Entry DOI: 10.2210/pdb3dzm/pdb
• Descriptor: Hypothetical conserved protein, CALCIUM ION, (HYDROXYETHYLOXY)TRI(ETHYLOXY)OCTANE, ... (4 entities in total)
• Functional Keywords: omp, thermus thermophilus hb27, beta-barrel, ttoa, unknown function
• Biological source: Thermus thermophilus
• Total number of polymer chains: 3
• Total formula weight: 70692.96

Authors

Brosig, A.,Diederichs, K. (deposition date: 2008-07-30, release date: 2008-12-23, Last modification date: 2024-11-13)

Primary citation

Brosig, A.,Nesper, J.,Boos, W.,Welte, W.,Diederichs, K.
Crystal structure of a major outer membrane protein from Thermus thermophilus HB27
J.Mol.Biol., 385:1445-1455, 2009

PubMed Abstract: The thermophilic eubacterium Thermus thermophilus belongs to one of the oldest branches of evolution and has a multilayered cell envelope that differs from that of modern Gram-negative bacteria. Its outer membrane contains integral outer membrane proteins (OMPs), of which only a few are characterized. TtoA, a new beta-barrel OMP, was identified by searching the genome sequence of strain HB27 for the presence of a C-terminal signature sequence. The structure of TtoA was determined to a resolution of 2.8 A, representing the first crystal structure of an OMP from a thermophilic bacterium. TtoA consists of an eight-stranded beta-barrel with a large extracellular part to which a divalent cation is bound. A five-stranded extracellular beta-sheet protrudes out of the membrane-embedded transmembrane barrel and is stabilized by a disulfide bridge. The edge of this beta-sheet forms crystal contacts that could mimic interactions with other proteins. In modern Gram-negative bacteria, the C-terminal signature sequence of OMPs is required for binding to an Omp85 family protein as a prerequisite for its assembly. We present hints that a similar assembly pathway exists in T. thermophilus by an in vitro binding assay, where unfolded TtoA binds to the Thermus Omp85 family protein TtOmp85, while a mutant without the signature sequence does not.

PubMed: 19101566
DOI: 10.1016/j.jmb.2008.12.003

Experimental method

X-RAY DIFFRACTION (2.801 Å)