کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1943423 1052664 2008 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Spectroscopic study on the communication between a heme a3 propionate, Asp399 and the binuclear center of cytochrome c oxidase from Paracoccus denitrificans
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
Spectroscopic study on the communication between a heme a3 propionate, Asp399 and the binuclear center of cytochrome c oxidase from Paracoccus denitrificans
چکیده انگلیسی

The proton pumping mechanism of cytochrome c oxidase on a molecular level is highly disputed. Recently theoretical calculations and real time electron transfer measurements indicated the involvement of residues in the vicinity of the ring A propionate of heme a3, including Asp399 and the CuB ligands His 325, 326. In this study we probed the interaction of Asp399 with the binuclear center and characterize the protonation state of its side chain. Redox induced FTIR difference spectra of mutations at the site in direct comparison to wild type, indicate that below pH 5 Asp 399 displays signals typical for the deprotonation of the acidic residue with reduction of the enzyme. Interestingly at a pH higher than 5, no contributions from Asp 399 are evident. In order to probe the interaction of the site with the binuclear center we followed the rebinding of CO by infrared spectroscopy for mutations on residue Asp399 to Glu, Asn and Leu. Previously different CO conformers have been identified for bacterial cytochrome c oxidases, and its pH dependent behaviour discussed to be relevant for catalysis. Interestingly we observe the lack of this pH dependency and a strong influence on the observable conformers for all mutants studied here, clearly suggesting a communication of the site with the heme-copper center and the nearby histidine residues.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1777, Issue 2, February 2008, Pages 220–226
نویسندگان
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