Proton input channel of cytochrome cbb(3) type oxidase in Rhodobacter capsulatus
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Dosyalar
Tarih
2011
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Current Biology Ltd
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Cytochrome cbb3 is a distinct member of the superfamily of respiratory heme-copper oxidases responsible for catalyzing the reduction of oxygen to water. As in all A-family, B-family, and C-family this reaction drives proton pumping across the membrane. Mutagenesis studies on family A have identified two conserved proton input channels: D and K. The residues in the A-family that are located in the proton channels are not conserved in the C-family. Since the C-type oxygen reductases have been shown to pump protons, presence of proton-conducting channels is obvious in this family that play analogous roles to the D-channel and/or K-channel. In this work, sequences were aligned to identify functionally important residues which may form the proton channels in the C-family. The functional importance of the residues was tested by site-directed mutagenesis using the cbb3 oxidase from Rhodobacter capsulatus. Several residues proposed to be part of the putative K-channel had significantly reduced catalytic activity upon mutations: T272A, Y280F/Y281F, T319M, N346V, and Y374F. The results support the proposal that in the C-family only one channel, analogous to the K-channel in the A-type oxygen reductases, functions for the delivery of both catalytic and pumped protons.
Açıklama
European Biotechnology Congress -- SEP 28-OCT 01, 2011 -- Istanbul, TURKEY
Anahtar Kelimeler
Rhodobacter Capsulatus
Kaynak
Current Opinion In Biotechnology
WoS Q Değeri
Q1
Scopus Q Değeri
Cilt
22
