This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
6cfw
From Proteopedia
cryoEM structure of a respiratory membrane-bound hydrogenase
Structural highlights
Function[MBHJ_PYRFU] Probable subunit of a hydrogen-evolving hydrogenase that utilizes protons both as a substrate for hydrogen production and proton translocation. Acts by coupling the redox reaction via ferredoxin and iron-sulfur (Fe-S) clusters to proton translocation across the membrane, thereby conserving the redox energy in a proton gradient.[1] [2] [3] [MBHLB_PYRFU] Beta subunit of a hydrogen-evolving hydrogenase that utilizes protons both as a substrate for hydrogen production and proton translocation. Acts by coupling the redox reaction via ferredoxin and iron-sulfur (Fe-S) clusters to proton translocation across the membrane thereby conserving the redox energy in a proton gradient.[4] [5] [6] [MBHLA_PYRFU] Alpha subunit of a hydrogen-evolving hydrogenase that utilizes protons both as a substrate for hydrogen production and proton translocation. Acts by coupling the redox reaction via ferredoxin and iron-sulfur (Fe-S) clusters to proton translocation across the membrane thereby conserving the redox energy in a proton gradient.[7] [8] [9] Publication Abstract from PubMedHydrogen gas-evolving membrane-bound hydrogenase (MBH) and quinone-reducing complex I are homologous respiratory complexes with a common ancestor, but a structural basis for their evolutionary relationship is lacking. Here, we report the cryo-EM structure of a 14-subunit MBH from the hyperthermophile Pyrococcus furiosus. MBH contains a membrane-anchored hydrogenase module that is highly similar structurally to the quinone-binding Q-module of complex I while its membrane-embedded ion-translocation module can be divided into a H(+)- and a Na(+)-translocating unit. The H(+)-translocating unit is rotated 180 degrees in-membrane with respect to its counterpart in complex I, leading to distinctive architectures for the two respiratory systems despite their largely conserved proton-pumping mechanisms. The Na(+)-translocating unit, absent in complex I, resembles that found in the Mrp H(+)/Na(+) antiporter and enables hydrogen gas evolution by MBH to establish a Na(+) gradient for ATP synthesis near 100 degrees C. MBH also provides insights into Mrp structure and evolution of MBH-based respiratory enzymes. Structure of an Ancient Respiratory System.,Yu H, Wu CH, Schut GJ, Haja DK, Zhao G, Peters JW, Adams MWW, Li H Cell. 2018 Apr 25. pii: S0092-8674(18)30403-3. doi: 10.1016/j.cell.2018.03.071. PMID:29754813[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
| ||||||||||||||||||||||
