Tags

Type your tag names separated by a space and hit enter

Critical factors determining dimerization of human antizyme inhibitor.
J Biol Chem. 2009 Sep 25; 284(39):26768-77.JB

Abstract

Ornithine decarboxylase (ODC) is the first enzyme involved in polyamine biosynthesis, and it catalyzes the decarboxylation of ornithine to putrescine. ODC is a dimeric enzyme, whereas antizyme inhibitor (AZI), a positive regulator of ODC that is homologous to ODC, exists predominantly as a monomer and lacks decarboxylase activity. The goal of this paper was to identify the essential amino acid residues that determine the dimerization of AZI. The nonconserved amino acid residues in the putative dimer interface of AZI (Ser-277, Ser-331, Glu-332, and Asp-389) were substituted with the corresponding residues in the putative dimer interface of ODC (Arg-277, Tyr-331, Asp-332, and Tyr-389, respectively). Analytical ultracentrifugation analysis was used to determine the size distribution of these AZI mutants. The size-distribution analysis data suggest that residue 331 may play a major role in the dimerization of AZI. Mutating Ser-331 to Tyr in AZI (AZI-S331Y) caused a shift from a monomer configuration to a dimer. Furthermore, in comparison with the single mutant AZI-S331Y, the AZI-S331Y/D389Y double mutant displayed a further reduction in the monomer-dimer K(d), suggesting that residue 389 is also crucial for AZI dimerization. Analysis of the triple mutant AZI-S331Y/D389Y/S277R showed that it formed a stable dimer (K(d) value = 1.3 microm). Finally, a quadruple mutant, S331Y/D389Y/S277R/E332D, behaved as a dimer with a K(d) value of approximately 0.1 microm, which is very close to that of the human ODC enzyme. The quadruple mutant, although forming a dimer, could still be disrupted by antizyme (AZ), further forming a heterodimer, and it could rescue the AZ-inhibited ODC activity, suggesting that the AZ-binding ability of the AZI dimer was retained.

Authors+Show Affiliations

Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19635796

Citation

Su, Kuo-Liang, et al. "Critical Factors Determining Dimerization of Human Antizyme Inhibitor." The Journal of Biological Chemistry, vol. 284, no. 39, 2009, pp. 26768-77.
Su KL, Liao YF, Hung HC, et al. Critical factors determining dimerization of human antizyme inhibitor. J Biol Chem. 2009;284(39):26768-77.
Su, K. L., Liao, Y. F., Hung, H. C., & Liu, G. Y. (2009). Critical factors determining dimerization of human antizyme inhibitor. The Journal of Biological Chemistry, 284(39), 26768-77. https://doi.org/10.1074/jbc.M109.007807
Su KL, et al. Critical Factors Determining Dimerization of Human Antizyme Inhibitor. J Biol Chem. 2009 Sep 25;284(39):26768-77. PubMed PMID: 19635796.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Critical factors determining dimerization of human antizyme inhibitor. AU - Su,Kuo-Liang, AU - Liao,Ya-Fan, AU - Hung,Hui-Chih, AU - Liu,Guang-Yaw, Y1 - 2009/07/27/ PY - 2009/7/29/entrez PY - 2009/7/29/pubmed PY - 2009/11/7/medline SP - 26768 EP - 77 JF - The Journal of biological chemistry JO - J. Biol. Chem. VL - 284 IS - 39 N2 - Ornithine decarboxylase (ODC) is the first enzyme involved in polyamine biosynthesis, and it catalyzes the decarboxylation of ornithine to putrescine. ODC is a dimeric enzyme, whereas antizyme inhibitor (AZI), a positive regulator of ODC that is homologous to ODC, exists predominantly as a monomer and lacks decarboxylase activity. The goal of this paper was to identify the essential amino acid residues that determine the dimerization of AZI. The nonconserved amino acid residues in the putative dimer interface of AZI (Ser-277, Ser-331, Glu-332, and Asp-389) were substituted with the corresponding residues in the putative dimer interface of ODC (Arg-277, Tyr-331, Asp-332, and Tyr-389, respectively). Analytical ultracentrifugation analysis was used to determine the size distribution of these AZI mutants. The size-distribution analysis data suggest that residue 331 may play a major role in the dimerization of AZI. Mutating Ser-331 to Tyr in AZI (AZI-S331Y) caused a shift from a monomer configuration to a dimer. Furthermore, in comparison with the single mutant AZI-S331Y, the AZI-S331Y/D389Y double mutant displayed a further reduction in the monomer-dimer K(d), suggesting that residue 389 is also crucial for AZI dimerization. Analysis of the triple mutant AZI-S331Y/D389Y/S277R showed that it formed a stable dimer (K(d) value = 1.3 microm). Finally, a quadruple mutant, S331Y/D389Y/S277R/E332D, behaved as a dimer with a K(d) value of approximately 0.1 microm, which is very close to that of the human ODC enzyme. The quadruple mutant, although forming a dimer, could still be disrupted by antizyme (AZ), further forming a heterodimer, and it could rescue the AZ-inhibited ODC activity, suggesting that the AZ-binding ability of the AZI dimer was retained. SN - 1083-351X UR - https://www.unboundmedicine.com/medline/citation/19635796/Critical_factors_determining_dimerization_of_human_antizyme_inhibitor_ L2 - http://www.jbc.org/cgi/pmidlookup?view=long&pmid=19635796 DB - PRIME DP - Unbound Medicine ER -