Contents：

一、演講者：周記源教授
(陽明大學生命科學學系暨基因體科學研究所教授)
學術專長：Enzymology, Structure biology, Molecular evolution

二、講題：Molecular evidence for the evolution from active enzyme to lens-refractive proteins

三、日期：106年3月21日（星期二），中午12點至下午2點

四、地點：化學館C308會議室

五、演講摘要：
Crystallins are soluble proteins in eye lenses that play an important role in the maintenance of lens transparency and optical clarity. Their aggregation can result in the formation of cataracts, which are the most common cause of blindness worldwide. Interestingly, some taxon-specific crystallins have been found to have structures that are related to cytosolic housekeeping enzymes. How lens crystallins evolved from such housekeeping enzymes is a most important question and answers to this question can greatly help our understanding of protein function, folding, and stability.
Among the crystallins, S-crystallin in the cephalopod lens has been shown to have an amino acid sequence similar to that of glutathione S-transferase (GST). As a major detoxification enzyme, GST catalyzes the conjugation of glutathione to various endogenous and xenobiotic electrophilic compounds. Previous studies have led to a model that involves multiple gene duplications and exon shuffling to allow the evolution from GST to a diverse and large family of S-crystallins. Up to the present there has been no direct structural information available that allows us to understand the reason for the differences.
Our findings revealed a novel structure for the cephalopod S-crystallin and provided crucial evidence that greatly aids our understanding of the evolution of S-crystallin. Loss of GST enzyme activity is linked to gaining the enhanced protein stability of S-crystallin and this occurs via glutathione binding. These changes can be considered to be the major driving force during the evolution of S-crystallin. Moreover, the secret of the stability of S-crystallin may help us find a strategy either to prevent or treat cataracts.

Time：

2017/03/21 12:00 ~ 2017/03/21 14:00

Registration period：

2017/02/20 08:00 ~ 2017/03/15 17:00

Location：

C308