منابع مشابه
Critical Role of Water Molecules in Proton Translocation by the Membrane-Bound Transhydrogenase.
The nicotinamide nucleotide transhydrogenase (TH) is an integral membrane enzyme that uses the proton-motive force to drive hydride transfer from NADH to NADP+ in bacteria and eukaryotes. Here we solved a 2.2-Å crystal structure of the TH transmembrane domain (Thermus thermophilus) at pH 6.5. This structure exhibits conformational changes of helix positions from a previous structure solved at p...
متن کاملFlagellar movement driven by proton translocation.
The bacterial flagellar motor couples ion flow to rotary motion at high speed and with apparently fixed stoichiometry. The functional properties of the motor are quite well understood, but its molecular mechanism remains unknown. Recent studies of motor physiology, coupled with mutational and biochemical studies of the components, put significant constraints on the mechanism. Rotation is probab...
متن کاملThe heterotrimer of the membrane-peripheral components of transhydrogenase and the alternating-site mechanism of proton translocation.
Transhydrogenase undergoes conformational changes to couple the redox reaction between NAD(H) and NADP(H) to proton translocation across a membrane. The protein comprises three components: dI, which binds NAD(H); dIII, which binds NADP(H); and dII, which spans the membrane. Experiments using isothermal titration calorimetry, analytical ultracentrifugation, and small angle x-ray scattering show ...
متن کاملProton translocation in proteins.
The active transport of protons across the low dielectric barrier imposed by biological membranes is accomplished by a plethora of proteins that span the ca. 40 ~ of the phospholipid bilayer. The free energy derived from the proton electrochemical potential established by the translocation of these protons can subsequently be used to drive vital chemical reactions of the cell, such as ATP synth...
متن کاملProton-Translocating Nicotinamide Nucleotide Transhydrogenase: A Structural Perspective
Nicotinamide nucleotide transhydrogenase (TH) is an enzyme complex in animal mitochondria and bacteria that utilizes the electrochemical proton gradient across membranes to drive the production of NADPH. The enzyme plays an important role in maintaining the redox balance of cells with implications in aging and a number of human diseases. TH exists as a homodimer with each protomer containing a ...
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ژورنال
عنوان ژورنال: FEBS Letters
سال: 2003
ISSN: 0014-5793
DOI: 10.1016/s0014-5793(03)01123-2