Conformational transition of VILIP1 and VILIP3 with binding of Mg2+ and Ca2+
| Autor: | Huei-Fen Jheng, 鄭蕙芬 |
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| Rok vydání: | 2005 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 93 Visinin-like proteins (VILIPs) are the members of EF-hand protein family, and their physiological functions are well-known to be regulated by Ca2+. The aim of the present study was to explore the structural changes of VILIP1 and VILIP3 upon the binding of Mg2+ and Ca2+. These results may allow us to deduce the molecular mechanism regulating the biological activities of VILIP1 and VILIP3. Fluorescence measurement showed that the binding of VILIP1 and VILIP3 with Mg2+ or Ca2+ were in a positive cooperative manners and their Ca2+-binding affinities were higher than that of Mg2+. The results of acrylamide quenching, thiol reactivity and protease susceptibility supported that the bindings of Mg2+ or Ca2+ induced the conformational transition of VILIP1 was differed from VILIP3. Furthermore, Ca2+ enhanced the thermal stability both of VILIP1 and VILIP3, while Mg2+ enhanced the thermal stability of VILIP1 but a decrease in structural stability by being with VILIP3. The results of size exclusion showed that, in the presence of Mg2+ or Ca2+, VILIP1 prefered to form dimer, whereas monomeric VILIP3 was exclusively produced. These observations strongly suggest that the binding of VILIP1 and VILIP3 with Mg2+ or Ca2+ causes a differential effect on the conformational changes. Pull down assay showed that VILIPs could form homo-oligomer as well as hetero-oligomer. Taken together, regardless of the presence or absence of Mg2+ or Ca2+, these findings suggest a possible route via the binding of Mg2+ or Ca2+ on affecting the physiological activity of VILIP1 and VILIP3. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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