Double‐Cubane [8Fe9S] Clusters: A Novel Nitrogenase‐Related Cofactor in Biology

• Published in: Chembiochem : a European journal of chemical biology Vol. 21; no. 12; pp. 1710 - 1716
• Main Authors: Jeoung, Jae‐Hun, Martins, Berta M., Dobbek, Holger
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 15-06-2020; John Wiley and Sons Inc
• Subjects: Acetylene; Activation; Adenosine triphosphatase; ATP; Clusters; Cofactors; Cubane; Electron transfer; Electrons; Enzymes; Homology; Iron; iron/sulfur cluster; Metallography; Minireview; Minireviews; Nitrogenase; Proteins; Reduction (metal working); small-molecule activation; Sulfur; electron transfer; ATP; small-molecule activation; iron/sulfur cluster; nitrogenase
• ISSN: 1439-4227; 1439-7633
• DOI: 10.1002/cbic.202000016

Three different types of electron‐transferring metallo‐ATPases are able to couple ATP hydrolysis to the reduction of low‐potential metal sites, thereby energizing an electron. Besides the Fe‐protein known from nitrogenase and homologous enzymes, two other kinds of ATPase with different scaffolds and cofactors are used to achieve a unidirectional, energetic, uphill electron transfer to either reduce inactive Co‐corrinoid‐containing proteins (RACE‐type activators) or a second iron‐sulfur cluster‐containing enzyme of a unique radical enzymes family (archerases). We have found a new cofactor in the latter enzyme family, that is, a double‐cubane cluster with two [4Fe4S] subclusters bridged by a sulfido ligand. An enzyme containing this cofactor catalyzes the ATP‐dependent reduction of small molecules, including acetylene. Thus, enzymes containing the double‐cubane cofactor are analogous in function and share some structural features with nitrogenases.
Two in one: Double cubane clusters are new cofactors found in two‐component enzymes. By coupling the hydrolysis of ATP to electron transfer to the double‐cubane cluster, they are able to catalyze the reduction of small molecules such as acetylene.