Molecular architectures and functions of radical enzymes and their (re)activating proteins.
Certain proteins utilize the high reactivity of radicals for catalysing chemically challenging reactions. These proteins contain or form a radical and therefore named 'radical enzymes'. Radicals are introduced by enzymes themselves or by (re)activating proteins called (re)activases. The X-ray structures of radical enzymes and their (re)activases revealed some structural features of these molecular apparatuses which solved common enigmas of radical enzymes—i.e. how the enzymes form or introduce radicals at the active sites, how they use the high reactivity of radicals for catalysis, how they suppress undesired side reactions of highly reactive radicals and how they are (re)activated when inactivated by extinction of radicals. This review highlights molecular architectures of radical B12 enzymes, radical SAM enzymes, tyrosyl radical enzymes, glycyl radical enzymes and their (re)activating proteins that support their functions. For generalization, comparisons of the recently reported structures of radical enzymes with those of canonical radical enzymes are summarized here.
Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan and.
Naoki
N
Shibata
Department of Bioscience and Biotechnology, Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan toraya@cc.okayama-u.ac.jp.
Tetsuo
T
Toraya
D000818:Animals; D055162:Biocatalysis; D020134:Catalytic Domain; D020536:Enzyme Activators / Q000737:chemistry / Q000378:metabolism*; D004793:Enzyme Reactivators / Q000737:chemistry / Q000378:metabolism*; D004798:Enzymes / Q000737:chemistry / Q000378:metabolism*; D005609:Free Radicals / Q000737:chemistry*; D006801:Humans; D008958:Models, Molecular; D011487:Protein Conformation
D020536:Enzyme Activators; D004793:Enzyme Reactivators; D004798:Enzymes; D005609:Free Radicals
(re)activase; S-adenosylmethionine; adenosylcobalamin; protein radical; radical enzyme