Residue 182 influences the second step of protein-tyrosine phosphatase-mediated catalysis
| Autor: | K.B. Moller, Ana K. Pedersen, H.S. Andersen, Lars Fogh Iversen, Niels Møller, Günther H.J. Peters, Xiao Ling Guo, S.B. Mortensen, Jette S. Kastrup, Zhong Yin Zhang |
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| Rok vydání: | 2004 |
| Předmět: |
Models
Molecular Stereochemistry Phenylalanine Phosphatase Protein tyrosine phosphatase environment and public health Biochemistry Catalysis Nitrophenols Residue (chemistry) Organophosphorus Compounds Aspartic acid Humans Histidine Amino Acid Sequence Enzyme kinetics Amino Acids Enzyme Inhibitors Phosphotyrosine Molecular Biology Protein Tyrosine Phosphatase Non-Receptor Type 1 chemistry.chemical_classification Aspartic Acid Hydrolysis Protein Tyrosine Phosphatase Non-Receptor Type 3 Cell Biology Amino acid enzymes and coenzymes (carbohydrates) Enzyme Models Chemical chemistry Mutagenesis Site-Directed Protein Tyrosine Phosphatases Vanadates Peptides Sequence Alignment Research Article |
| Zdroj: | Biochemical Journal. 378:421-433 |
| ISSN: | 1470-8728 0264-6021 |
| DOI: | 10.1042/bj20030565 |
| Popis: | Previous enzyme kinetic and structural studies have revealed a critical role for Asp181 (PTP1B numbering) in PTP (protein-tyrosine phosphatase)-mediated catalysis. In the E-P (phosphoenzyme) formation step, Asp181 functions as a general acid, while in the E-P hydrolysis step it acts as a general base. Most of our understanding of the role of Asp181 is derived from studies with the Yersinia PTP and the mammalian PTP1B, and to some extent also TC (T-cell)-PTP and the related PTPα and PTP∊. The neighbouring residue 182 is a phenylalanine in these four mammalian enzymes and a glutamine in Yersinia PTP. Surprisingly, little attention has been paid to the fact that this residue is a histidine in most other mammalian PTPs. Using a reciprocal single-point mutational approach with introduction of His182 in PTP1B and Phe182 in PTPH1, we demonstrate here that His182-PTPs, in comparison with Phe182-PTPs, have significantly decreased kcat values, and to a lesser degree, decreased kcat/Km values. Combined enzyme kinetic, X-ray crystallographic and molecular dynamics studies indicate that the effect of His182 is due to interactions with Asp181 and with Gln262. We conclude that residue 182 can modulate the functionality of both Asp181 and Gln262 and therefore affect the E-P hydrolysis step of PTP-mediated catalysis. |
| Databáze: | OpenAIRE |
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