1H NMR Study of the Influence of Hemin Vinyl→Methyl Substitution on the Interaction between theC-Terminus and Substrate and the 'Aging' of the Heme Oxygenase fromNeisseria meningitidis: Induction of Active Site Structural Heterogeneity by a Two-Fold Symmetric Hemin
| Autor: | Yangzhong Liu, James D. Satterlee, Li-Hua Ma, Gerd N. La Mar, Xuhong Zhang, Tadashi Yoshida |
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| Rok vydání: | 2006 |
| Předmět: | |
| Zdroj: | Biochemistry. 45:13875-13888 |
| ISSN: | 1520-4995 0006-2960 |
| Popis: | Solution 1H NMR has been used to characterize the active site molecular and electronic structure of the cyanide-inhibited 2,4-dimethyldeuterohemin complex of the heme oxygenase from Neisseria meningitidis (NmHO) with respect to the mode of interaction of the C-terminus with the substrate and the spontaneous “aging” of NmHO that results in the cleavage of the C-terminal Arg208-His209 dipeptide. The structure of the portion involving residues Ala12-Phe192 is found to be essentially identical to that of the protohemin complex in either solution or crystal. However, His207 from the C-terminus is found to interact strongly with the substrate 1CH3, as opposed to the 8CH3 in the protohemin complex. The different mode of interaction of His207 with the alternate substrates is attributed to the 2-vinyl group of protohemin sterically interfering with the optimal orientation of the proximal helix Asp27 carboxylate that serves as acceptor to the strong H-bond by the peptide of His207. The 2,4-dimethyldeuterohemin HO c... |
| Databáze: | OpenAIRE |
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