Stability of the H-cluster under whole-cell conditions—formation of an Htrans-like state and its reactivity towards oxygen

Journal article

Hydrogenases are metalloenzymes that catalyze the reversible oxidation of molecular hydrogen into protons and electrons. For this purpose, [FeFe]-hydrogenases utilize a hexanuclear iron cofactor, the H-cluster. This biologically unique cofactor provides the enzyme with outstanding catalytic activities, but it is also highly oxygen sensitive. Under in vitro conditions, oxygen stable forms of the H-cluster denoted Htrans and Hinact can be generated via treatment with sulfide under oxidizing conditions. Herein, we show that an Htrans-like species forms spontaneously under intracellular conditions on a time scale of hours, concurrent with the cells ceasing H2 production. Addition of cysteine or sulfide during the maturation promotes the formation of this H-cluster state. Moreover, it is found that formation of the observed Htrans-like species is influenced by both steric factors and proton transfer, underscoring the importance of outer coordination sphere effects on H-cluster reactivity

Authors: Lorenzi, M; Ceccaldi, P; Rodríguez-Maciá, P; Redman, HJ; Zamader, A

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer
• Journal: JBIC Journal of Biological Inorganic Chemistry
• Volume: 27
• Issue: 3
• Pages: 345-355
• Publication date: 2022-03-08
• DOI: 10.1007/s00775-022-01928-5
• EISSN: 1432-1327
• ISSN: 0949-8257
• Language: English
• Keywords: Chemistry; Cofactor; Stereochemistry; Reactivity (psychology); Iron–sulfur cluster; Organic chemistry; Catalysis; Oxygen; Hydrogen; Molecular oxygen; Hydrogenase; Biochemistry; Cluster (spacecraft); Combinatorial chemistry; Photochemistry; Enzyme