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Publication Abstract from PubMed

Aldehyde dehydrogenases (ALDH) form a superfamily of dimeric or tetrameric enzymes that catalyze the oxidation of a broad range of aldehydes into their corresponding carboxylic acids with the concomitant reduction of the cofactor NAD(P) into NAD(P)H. Despite their varied polypeptide chain length and oligomerisation states, ALDHs possess a conserved architecture of three domains: the catalytic domain, NAD(P)(+) binding domain, and the oligomerization domain. Here, we describe the structure and function of the ALDH from Thermus thermophilus (ALDHTt) which exhibits non-canonical features of both dimeric and tetrameric ALDH and a previously uncharacterized C-terminal arm extension forming novel interactions with the N-terminus in the quaternary structure. This unusual tail also interacts closely with the substrate entry tunnel in each monomer providing further mechanistic detail for the recent discovery of tail-mediated activity regulation in ALDH. However, due to the novel distal extension of the tail of ALDHTt and stabilizing termini-interactions, the current model of tail-mediated substrate access is not apparent in ALDHTt. The discovery of such a long tail in a deeply and early branching phylum such as Deinococcus-Thermus indicates that ALDHTt may be an ancestral or primordial metabolic model of study. This structure provides invaluable evidence of how metabolic regulation has evolved and provides a link to early enzyme regulatory adaptations.

The quaternary structure of Thermus thermophilus aldehyde dehydrogenase is stabilized by an evolutionary distinct C-terminal arm extension.,Hayes K, Noor M, Djeghader A, Armshaw P, Pembroke T, Tofail S, Soulimane T Sci Rep. 2018 Sep 6;8(1):13327. doi: 10.1038/s41598-018-31724-8. PMID:30190503^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.