5-demethoxyubiquinone hydroxylase, mitochondrial (DMQ hydroxylase) (EC 1.14.99.60) (Timing protein clk-1 homolog) (Ubiquinone biosynthesis monooxygenase COQ7)
1_MSCAG 6_ AAAAP 11_ RLWRL 16_ RPGAR 21_ RSLSA 26_ YGRRT 31_ SVRFR 36_ SSGMT 41_ LDNIS 46_ RAAVD 51_ RIIRV 56_ DHAGE 61_ YGANR 66_ IYAGQ 71_ MAVLG 76_ RTSVG 81_ PVIQK 86_ MWDQE 91_ KDHLK 96_ KFNEL 101_ MVTFR 106_ VRPTV 111_ LMPLW 116_ NVLGF 121_ ALGAG 126_ TALLG 131_ KEGAM 136_ ACTVA 141_ VEESI 146_ AHHYN 151_ NQIRT 156_ LMEED 161_ PEKYE 166_ ELLQL 171_ IKKFR 176_ DEELE 181_ HHDIG 186_ LDHDA 191_ ELAPA 196_ YAVLK 201_ SIIQA 206_ GCRVA 211_IYLSE
1: Catalyzes the hydroxylation of the 5-methoxy-2-methyl-3-(all-trans-polyprenyl)benzoquinone at the C6 position and participates in the biosynthesis of ubiquinone (Probable). Catalyzes the reaction through a substrate-mediated reduction pathway, whereby NADH shuttles electrons to 5-methoxy-2-methyl-3-(all-trans-decaprenyl)benzoquinone, which then transfers the electrons to the two Fe(3+) centers (PubMed:23445365). The binding of 5-methoxy-2-methyl-3-(all-trans-polyprenyl)benzoquinone (DMQn) mediates reduction of the diiron center by nicotinamide adenine dinucleotide (NADH) and initiates oxygen activation for subsequent DMQ hydroxylation (PubMed:23445365). The physiological substrates are 5-methoxy-2-methyl-3-(all-trans-nonaprenyl)benzoquinone (DMQ(9)) and 5-methoxy-2-methyl-3-(all-trans-decaprenyl)benzoquinone (DMQ(10)), however in vitro the enzyme does not have any specificity concerning the length of the polyprenyl tail, and accepts tails of various lengths with similar efficiency (PubMed:23445365, PubMed:28409910). Also has a structural role in the COQ enzyme complex, stabilizing other COQ polypeptides. Involved in lifespan determination in a ubiquinone-independent manner (By similarity). Plays a role in modulating mitochondrial stress responses, acting in the nucleus, perhaps via regulating gene expression, independent of its characterized mitochondrial function in ubiquinone biosynthesis (PubMed:25961505)