Dataset Information

A radical on the Met-Tyr-Trp modification required for catalase activity in catalase-peroxidase is established by isotopic labeling and site-directed mutagenesis.

ABSTRACT: A transient tyrosyl-like radical with a narrow doublet X-band EPR signal is present during catalase turnover by Mycobacterium tuberculosis catalase-peroxidase (KatG). Labeling of KatG with beta-methylene-deuterated tyrosine causes a collapse of the doublet to a singlet, while for 3,5-ring-deuterated tyrosine-labeled enzyme, no changes occur in the EPR signal. Except for the replacement Tyr229Phe, all other single-tyrosine mutants of KatG exhibit the same narrow doublet EPR signal and catalase activity similar to that of the wild-type enzyme. These findings confirm that this catalytically competent radical is associated with Tyr229, whose 3' and 5' protons are replaced as a result of cross-links with neighboring Met255 and Trp107 side chains in the post-translationally modified enzyme containing a distal-side Met255-Tyr229-Trp107 adduct.

SUBMITTER: Zhao X

PROVIDER: S-EPMC2897066 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A radical on the Met-Tyr-Trp modification required for catalase activity in catalase-peroxidase is established by isotopic labeling and site-directed mutagenesis.

Zhao Xiangbo X Suarez Javier J Khajo Abdelahad A Yu Shengwei S Metlitsky Leonid L Magliozzo Richard S RS

Journal of the American Chemical Society 20100601 24

A transient tyrosyl-like radical with a narrow doublet X-band EPR signal is present during catalase turnover by Mycobacterium tuberculosis catalase-peroxidase (KatG). Labeling of KatG with beta-methylene-deuterated tyrosine causes a collapse of the doublet to a singlet, while for 3,5-ring-deuterated tyrosine-labeled enzyme, no changes occur in the EPR signal. Except for the replacement Tyr229Phe, all other single-tyrosine mutants of KatG exhibit the same narrow doublet EPR signal and catalase ac ...[more]

PMID: 20507091

Similar Datasets

Project description:Scope: As a result of population ageing, the number of Alzheimer’s disease (AD) patients has rapidly increased. There are many hypothesises on the pathogenesis of AD, but its detailed molecular mechanism is still unknown, and so no effective preventive or therapeutic measures have been established. Some reports showed a decrease in levels of norepinephrine (NE) has been suspected to be involved in the decline of cognitive function in AD patients and NE concentrations were decreased in postmortem AD patient brains. Tyr-Trp was identified as being the most effective dipeptide in enhancing norepinephrine (NE) synthesis and metabolism. And Tyr-Trp treatment ameliorated the short-term memory dysfunction in AD model mice caused by amyloid beta (Aβ) 25-35. So, the purpose of this study was to investigate the preventive or/and protective effects of Tyr-Trp administration in AD model mice. Methods and results: ddY mice were fed normal diet. After 7 days of feeding, mice were divided into 3 groups (n=10 per group) as follows: the sham group, which received saline administration and distilled water injection; the Aβ group, which received saline administration and Aβ peptides 25–35 injection; and the Aβ+YW group, which received Tyr-Trp administration and Aβ peptides 25–35 injection. Tyr-Trp was orally administered Tyr-Trp (100 mg kg-1 day-1, twice a day), starting 7 days before Aβ peptides injection. The other groups received oral administration of saline (5 mL kg-1). After Aβ peptides injection or sham operation, each groups received every oral administration. DAN microarray showed that Tyrosine hydroxylase, dopa decarboxylase and dopamine receptor D2 mRNA expressions which were downregulated in Aβ group comparing with sham group were upregulated in Aβ+YW group comparing with Aβ group. In addition, quinoid dihydropteridine reductase mRNA expression which wasn’t changed in Aβ group comparing with sham group was upregulated in Aβ+YW group comparing with Aβ group. Conclusions: These results suggest that Tyr-Trp administration might ameliorate the short-term memory dysfunction in AD model mice because of enhancing norepinephrine (NE) synthesis and metabolism through metabolism of both Tyr and Trp.

Dataset Information

A radical on the Met-Tyr-Trp modification required for catalase activity in catalase-peroxidase is established by isotopic labeling and site-directed mutagenesis.

Publications

A radical on the Met-Tyr-Trp modification required for catalase activity in catalase-peroxidase is established by isotopic labeling and site-directed mutagenesis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets