1l2p
From Proteopedia
ATP Synthase b Subunit Dimerization Domain
Structural highlights
Function[ATPF_ECOLI] F(1)F(0) ATP synthase produces ATP from ADP in the presence of a proton or sodium gradient. F-type ATPases consist of two structural domains, F(1) containing the extramembraneous catalytic core and F(0) containing the membrane proton channel, linked together by a central stalk and a peripheral stalk. During catalysis, ATP synthesis in the catalytic domain of F(1) is coupled via a rotary mechanism of the central stalk subunits to proton translocation (By similarity).[1] Component of the F(0) channel, it forms part of the peripheral stalk, linking F(1) to F(0) (By similarity).[2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe b subunit of E. coli F(0)F(1)-ATPase links the peripheral F(1) subunits to the membrane-integral F(0) portion and functions as a "stator", preventing rotation of F(1). The b subunit is present as a dimer in ATP synthase, and residues 62-122 are required to mediate dimerization. To understand how the b subunit dimer is formed, we have studied the structure of the isolated dimerization domain, b(62-122). Analytical ultracentrifugation and solution small-angle X-ray scattering (SAXS) indicate that the b(62-122) dimer is extremely elongated, with a frictional ratio of 1.60, a maximal dimension of 95 A, and a radius of gyration of 27 A, values that are consistent with an alpha-helical coiled-coil structure. The crystal structure of b(62-122) has been solved and refined to 1.55 A. The protein crystallized as an isolated, monomeric alpha helix with a length of 90 A. Combining the crystal structure of monomeric b(62-122) with SAXS data from the dimer in solution, we have constructed a model for the b(62-122) dimer in which the two helices form a coiled coil with a right-handed superhelical twist. Analysis of b sequences from E. coli and other prokaryotes indicates conservation of an undecad repeat, which is characteristic of a right-handed coiled coil and consistent with our structural model. Mutation of residue Arg-83, which interrupts the undecad pattern, to alanine markedly stabilized the dimer, as expected for the proposed two-stranded, right-handed coiled-coil structure. The "second stalk" of Escherichia coli ATP synthase: structure of the isolated dimerization domain.,Del Rizzo PA, Bi Y, Dunn SD, Shilton BH Biochemistry. 2002 May 28;41(21):6875-84. PMID:12022893[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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