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-Structure paper
タイトル | Cryo-EM of CcsBA reveals the basis for cytochrome c biogenesis and heme transport. |
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ジャーナル・号・ページ | Nat Chem Biol, Vol. 18, Issue 1, Page 101-108, Year 2022 |
掲載日 | 2021年12月20日 |
![]() | Deanna L Mendez / Ethan P Lowder / Dustin E Tillman / Molly C Sutherland / Andrea L Collier / Michael J Rau / James A J Fitzpatrick / Robert G Kranz / ![]() |
PubMed 要旨 | Although the individual structures and respiratory functions of cytochromes are well studied, the structural basis for their assembly, including transport of heme for attachment, are unknown. We ...Although the individual structures and respiratory functions of cytochromes are well studied, the structural basis for their assembly, including transport of heme for attachment, are unknown. We describe cryo-electron microscopy (cryo-EM) structures of CcsBA, a bifunctional heme transporter and cytochrome c (cyt c) synthase. Models built from the cryo-EM densities show that CcsBA is trapped with heme in two conformations, herein termed the closed and open states. The closed state has heme located solely at a transmembrane (TM) site, with a large periplasmic domain oriented such that access of heme to the cytochrome acceptor is denied. The open conformation contains two heme moieties, one in the TM-heme site and another in an external site (P-heme site). The presence of heme in the periplasmic site at the base of a chamber induces a large conformational shift that exposes the heme for reaction with apocytochrome c (apocyt c). Consistent with these structures, in vivo and in vitro cyt c synthase studies suggest a mechanism for transfer of the periplasmic heme to cytochrome. |
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手法 | EM (単粒子) |
解像度 | 3.56 - 4.14 Å |
構造データ | EMDB-24941, PDB-7s9y: EMDB-24942, PDB-7s9z: |
化合物 | ![]() ChemComp-HEB: ![]() ChemComp-PTY: |
由来 |
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![]() | MEMBRANE PROTEIN / Cytochrome c biogenesis / Heme transporter / Heme lyase |