Three-Dimensional Structure of the Nonaheme Cytochrome c from Desulfovibrio desulfuricans Essex in the Fe(III) State at 1.89 Å Resolution

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• 作者：Stephan Umhau ; Gü ; nter Fritz ; Kay Diederichs ; Jason Breed ; Wolfram Welte ; and Peter M. H. Kroneck
• 刊名：Biochemistry
• 出版年：2001
• 出版时间：February 6, 2001
• 年：2001
• 卷：40
• 期：5
• 页码：1308 - 1316
• 全文大小：1073K
• 年卷期：v.40,no.5(February 6, 2001)
• ISSN：1520-4995

文摘

A nine heme group containing cytochrome c isolated from the soluble and membrane fractionsof Desulfovibrio desulfuricans Essex, termed nonaheme cytochrome c, was crystallized, and the structurewas solved using the multiple wavelength anomalous dispersion (MAD) phasing method. Refinementwas carried out to a resolution of 1.89 Å, and anisotropic temperature factors were addressed to the ironand sulfur atoms in the model. The structure revealed two cytochrome c₃ like domains with the typicalarrangement of four heme centers. Both domains flanked an extra heme buried under the protein surface.This heme is held in position by loop extensions in each of the two domains. Although both the N- andC-terminal tetraheme domains exhibit a fold and heme arrangement very similar to that of cytochrome c₃,they differ considerably in their loop extensions and electrostatic surface. Analysis of the structure providesevidence for a different function of both domains, namely, anchoring the protein in a transmembranouscomplex with the N-terminal domain and formation of an electron-transfer complex with hydrogenase bythe C-terminal domain.