QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: mol.106.023275v1 70/1/120    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hamamoto, H. Articles by Sakaki, T. Search for Related Content PubMed PubMed Citation Articles by Hamamoto, H. Articles by Sakaki, T.

Structure-Function Analysis of Vitamin D 24-Hydroxylase (CYP24A1) by Site-Directed Mutagenesis: Amino Acid Residues Responsible for Species-Based Difference of CYP24A1 between Humans and Rats

Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan (H.H., T.K., N.U., K.I.); Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan (H.M., K.Y., S.Y.); Biotechnology Research Center, Faculty of Engineering, Toyama Prefectural University, Toyama, Japan (M.K., T.S.); and Laboratory of Nutrition, Koshien University, Nishinomiya, Japan (M.O.)

Our previous studies revealed the species-based difference of CYP24A1-dependent vitamin D metabolism. Although human CYP24A1 catalyzes both C-23 and C-24 oxidation pathways, rat CYP24A1 shows almost no C-23 oxidation pathway. We tried to identify amino acid residues that cause the species-based difference by site-directed mutagenesis. In the putative substrate-binding regions, amino acid residue of rat CYP24A1 was converted to the corresponding residue of human CYP24A1. Among eight mutants examined, T416M and I500T showed C-23 oxidation pathway. In addition, the mutant I500F showed quite a different metabolism of 1,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃] from both human and rat CYP24A1. These results strongly suggest that the amino acid residues at positions 416 and 500 play a crucial role in substrate binding and greatly affect substrate orientation. A three-dimensional model of CYP24A1 indicated that the A-ring and triene part of 1,25(OH)₂D₃ could be located close to amino acid residues at positions 416 and 500, respectively. Our findings provide useful information for the development of new vitamin D analogs for clinical use.

Address correspondence to: Toshiyuki Sakaki, Biotechnology Research Center, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan. E-mail: tsakaki{at}pu-toyama.ac.jp

This article has been cited by other articles:

				N. Urushino, S. Nakabayashi, M. A. Arai, A. Kittaka, T. C. Chen, K. Yamamoto, K. Hayashi, S. Kato, M. Ohta, M. Kamakura, et al. Kinetic Studies of 25-Hydroxy-19-nor-vitamin D3 and 1{alpha},25-Dihydroxy-19-nor-vitamin D3 Hydroxylation by CYP27B1 and CYP24A1 Drug Metab. Dispos., September 1, 2007; 35(9): 1482 - 1488. [Abstract] [Full Text] [PDF]

				D. E. Prosser, M. Kaufmann, B. O'Leary, V. Byford, and G. Jones Single A326G mutation converts human CYP24A1 from 25-OH-D3-24-hydroxylase into -23-hydroxylase, generating 1{alpha},25-(OH)2D3-26,23-lactone PNAS, July 31, 2007; 104(31): 12673 - 12678. [Abstract] [Full Text] [PDF]