Hydrophobicity of residue 108 specifically affects the affinity of human beta-carotene 15,15'-monooxygenase for substrates with two ionone rings.
The Lys residue at position 108 of human beta-carotene 15,15'-monooxygenase is located on the outside surface of the active tunnel of the enzyme. Hydrophobic mutations (K108F and K108L) at this position substantially decreased the affinity of the enzyme for substrates with ionone rings at both ends, such as alpha-carotene, beta-carotene, and beta-cryptoxanthine. In contrast, these mutations had little effect on the affinity of the enzyme for substrates with one ionone ring and one open-chain end, such as beta-apo-4'-carotenal and beta-apo-8'-carotenal. The residue 108 may be related to the indirect interaction with the second ionone ring of the substrates with two ionone rings.
Kim
Yeong-Su
YS
Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, Republic of Korea.
Park
Chang-Su
CS
Oh
Deok-Kun
DK
D000595:Amino Acid Sequence; D002338:Carotenoids / Q000378:metabolism; D065366:Cryptoxanthins; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008239:Lysine / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D045792:Norisoprenoids / Q000378:metabolism*; D011485:Protein Binding; D016415:Sequence Alignment; D013379:Substrate Specificity; D024341:Xanthophylls / Q000378:metabolism; D019207:beta Carotene / Q000378:metabolism; D050559:beta-Carotene 15,15'-Monooxygenase / Q000737:chemistry* / Q000378:metabolism*
D065366:Cryptoxanthins; D045792:Norisoprenoids; D024341:Xanthophylls; C110652:beta-apo-8'-carotenal; D019207:beta Carotene; D002338:Carotenoids; C041635:alpha-carotene; C493358:BCO1 protein, human; D050559:beta-Carotene 15,15'-Monooxygenase; D008239:Lysine