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Kinetic Characterization and Catalytic Mechanism of N-Acetylornithine Aminotransferase Encoded by slr1022 Gene from Synechocystis sp. PCC6803

The enzyme encoded by slr1022 gene from Synechocystis sp. PCC6803 was reported to function as N-acetylornithine aminotransferase, γ-aminobutyric acid aminotransferase, and ornithine aminotransferase, which played important roles in multiple metabolic pathways. Among these functions, N-acetylornithin...

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Autores principales: Li, Zhi-Min, Bai, Fumei, Wang, Xiaoqin, Xie, Congcong, Wan, Yuting, Li, Yating, Liu, Jianping, Li, Zhimin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10057298/
https://www.ncbi.nlm.nih.gov/pubmed/36982927
http://dx.doi.org/10.3390/ijms24065853
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author Li, Zhi-Min
Bai, Fumei
Wang, Xiaoqin
Xie, Congcong
Wan, Yuting
Li, Yating
Liu, Jianping
Li, Zhimin
author_facet Li, Zhi-Min
Bai, Fumei
Wang, Xiaoqin
Xie, Congcong
Wan, Yuting
Li, Yating
Liu, Jianping
Li, Zhimin
author_sort Li, Zhi-Min
collection PubMed
description The enzyme encoded by slr1022 gene from Synechocystis sp. PCC6803 was reported to function as N-acetylornithine aminotransferase, γ-aminobutyric acid aminotransferase, and ornithine aminotransferase, which played important roles in multiple metabolic pathways. Among these functions, N-acetylornithine aminotransferase catalyzes the reversible conversion of N-acetylornithine to N-acetylglutamate-5-semialdehyde with PLP as cofactor, which is a key step in the arginine biosynthesis pathway. However, the investigation of the detailed kinetic characteristics and catalytic mechanism of Slr1022 has not been carried out yet. In this study, the exploration of kinetics of recombinant Slr1022 illustrated that Slr1022 mainly functioned as N-acetylornithine aminotransferase with low substrate specificity to γ-aminobutyric acid and ornithine. Kinetic assay of Slr1022 variants and the model structure of Slr1022 with N-acetylornithine-PLP complex revealed that Lys280 and Asp251 residues were the key amino acids of Slr1022. The respective mutation of the above two residues to Ala resulted in the activity depletion of Slr1022. Meanwhile, Glu223 residue was involved in substrate binding and it served as a switch between the two half reactions. Other residues such as Thr308, Gln254, Tyr39, Arg163, and Arg402 implicated a substrate recognition and catalytic process of the reaction. The results of this study further enriched the understanding of the catalytic kinetics and mechanism of N-acetylornithine aminotransferase, especially from cyanobacteria.
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spelling pubmed-100572982023-03-30 Kinetic Characterization and Catalytic Mechanism of N-Acetylornithine Aminotransferase Encoded by slr1022 Gene from Synechocystis sp. PCC6803 Li, Zhi-Min Bai, Fumei Wang, Xiaoqin Xie, Congcong Wan, Yuting Li, Yating Liu, Jianping Li, Zhimin Int J Mol Sci Article The enzyme encoded by slr1022 gene from Synechocystis sp. PCC6803 was reported to function as N-acetylornithine aminotransferase, γ-aminobutyric acid aminotransferase, and ornithine aminotransferase, which played important roles in multiple metabolic pathways. Among these functions, N-acetylornithine aminotransferase catalyzes the reversible conversion of N-acetylornithine to N-acetylglutamate-5-semialdehyde with PLP as cofactor, which is a key step in the arginine biosynthesis pathway. However, the investigation of the detailed kinetic characteristics and catalytic mechanism of Slr1022 has not been carried out yet. In this study, the exploration of kinetics of recombinant Slr1022 illustrated that Slr1022 mainly functioned as N-acetylornithine aminotransferase with low substrate specificity to γ-aminobutyric acid and ornithine. Kinetic assay of Slr1022 variants and the model structure of Slr1022 with N-acetylornithine-PLP complex revealed that Lys280 and Asp251 residues were the key amino acids of Slr1022. The respective mutation of the above two residues to Ala resulted in the activity depletion of Slr1022. Meanwhile, Glu223 residue was involved in substrate binding and it served as a switch between the two half reactions. Other residues such as Thr308, Gln254, Tyr39, Arg163, and Arg402 implicated a substrate recognition and catalytic process of the reaction. The results of this study further enriched the understanding of the catalytic kinetics and mechanism of N-acetylornithine aminotransferase, especially from cyanobacteria. MDPI 2023-03-19 /pmc/articles/PMC10057298/ /pubmed/36982927 http://dx.doi.org/10.3390/ijms24065853 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Li, Zhi-Min
Bai, Fumei
Wang, Xiaoqin
Xie, Congcong
Wan, Yuting
Li, Yating
Liu, Jianping
Li, Zhimin
Kinetic Characterization and Catalytic Mechanism of N-Acetylornithine Aminotransferase Encoded by slr1022 Gene from Synechocystis sp. PCC6803
title Kinetic Characterization and Catalytic Mechanism of N-Acetylornithine Aminotransferase Encoded by slr1022 Gene from Synechocystis sp. PCC6803
title_full Kinetic Characterization and Catalytic Mechanism of N-Acetylornithine Aminotransferase Encoded by slr1022 Gene from Synechocystis sp. PCC6803
title_fullStr Kinetic Characterization and Catalytic Mechanism of N-Acetylornithine Aminotransferase Encoded by slr1022 Gene from Synechocystis sp. PCC6803
title_full_unstemmed Kinetic Characterization and Catalytic Mechanism of N-Acetylornithine Aminotransferase Encoded by slr1022 Gene from Synechocystis sp. PCC6803
title_short Kinetic Characterization and Catalytic Mechanism of N-Acetylornithine Aminotransferase Encoded by slr1022 Gene from Synechocystis sp. PCC6803
title_sort kinetic characterization and catalytic mechanism of n-acetylornithine aminotransferase encoded by slr1022 gene from synechocystis sp. pcc6803
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10057298/
https://www.ncbi.nlm.nih.gov/pubmed/36982927
http://dx.doi.org/10.3390/ijms24065853
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