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Loss of Function in Zeaxanthin Epoxidase of Dunaliella tertiolecta Caused by a Single Amino Acid Mutation within the Substrate-Binding Site.
- Source :
-
Marine drugs [Mar Drugs] 2018 Nov 01; Vol. 16 (11). Date of Electronic Publication: 2018 Nov 01. - Publication Year :
- 2018
-
Abstract
- The zea1 mutant of marine microalga Dunaliella tertiolecta accumulates zeaxanthin under normal growth conditions, and its phenotype has been speculated to be related to zeaxanthin epoxidase (ZEP). In this study, we isolated the ZEP gene from both wild-type D. tertiolecta and the mutant. We found that the zea1 mutant has a point mutation of the 1337th nucleotide of the ZEP sequence (a change from guanine to adenine), resulting in a change of glycine to aspartate in a highly conserved region in the catalytic domain. Similar expression levels of ZEP mRNA and protein in both wild-type and zea1 were confirmed by using qRT-PCR and western blot analysis, respectively. Additionally, the enzyme activity analysis of ZEPs in the presence of cofactors showed that the inactivation of ZEP in zea1 was not caused by deficiency in the levels of cofactors. From the predicted three-dimensional ZEP structure of zea1 , we observed a conformational change on the substrate-binding site in the ZEP. A comparative analysis of the ZEP structures suggested that the conformational change induced by a single amino acid mutation might impact the interaction between the substrate and substrate-binding site, resulting in loss of zeaxanthin epoxidase function.
- Subjects :
- Amino Acid Sequence genetics
Catalytic Domain genetics
Chlorophyta metabolism
Loss of Function Mutation
Microalgae metabolism
Models, Molecular
Oxidoreductases metabolism
Point Mutation
Algal Proteins genetics
Chlorophyta genetics
Microalgae genetics
Oxidoreductases genetics
Zeaxanthins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1660-3397
- Volume :
- 16
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- Marine drugs
- Publication Type :
- Academic Journal
- Accession number :
- 30388729
- Full Text :
- https://doi.org/10.3390/md16110418