Alterations of structure and hydrolase activity of parkinsonism-associated human ubiquitin carboxyl-terminal hydrolase L1 variants.
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Nishikawa K, Li H, Kawamura R, Osaka H, Wang YL, Hara Y, Hirokawa T, Manago Y, Amano T, Noda M, Aoki S, Wada K
Alterations of structure and hydrolase activity of parkinsonism-associated human ubiquitin carboxyl-terminal hydrolase L1 variants.
Biochem Biophys Res Commun. 2003 Apr 25;304(1):176-83.
- PubMed ID
- 12705903 [ View in PubMed]
- Abstract
Ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) is a neuron-specific ubiquitin recycling enzyme. A mutation at residue 93 and polymorphism at residue 18 within human UCH-L1 are linked to familial Parkinson's disease and a decreased Parkinson's disease risk, respectively. Thus, we constructed recombinant human UCH-L1 variants and examined their structure (using circular dichroism) and hydrolase activities. We confirmed that an I93M substitution results in a decrease in kcat (45.6%) coincident with an alteration in alpha-helical content. These changes may contribute to the pathogenesis of Parkinson's disease. In contrast, an S18Y substitution results in an increase in kcat (112.6%) without altering the circular dichroistic spectrum. These data suggest that UCH-L1 hydrolase activity may be inversely correlated with Parkinson's disease risk and that the hydrolase activity is protective against the disease. Furthermore, we found that oxidation of UCH-L1 by 4-hydroxynonenal, a candidate for endogenous mediator of oxidative stress-induced neuronal cell death, results in a loss of hydrolase activity. Taken together, these results suggest that further studies of altered UCH-L1 hydrolase function may provide new insights into a possible common pathogenic mechanism between familial and sporadic Parkinson's disease.