Structure-activity relationship studies of gomesin:: Importance of the disulfide bridges for conformation, bioactivities, and serum stability
Structure-activity relationship studies of gomesin:: Importance of the disulfide bridges for conformation, bioactivities, and serum stability
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DOI：
10.1002/bip.20396
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发表时间：
2006-01-01
期刊：
影响因子：
2.9
通讯作者：
Miranda, A
中科院分区：
文献类型：
--
作者：
Fázio, MA;Oliveira, VX;Miranda, A
Gomesin是从巴西蜘蛛的血细胞中分离的抗微生物肽，其含有两个二硫键Cys（2-15）/Cys（6-11）并呈现β-发夹结构。为了研究二硫键对戈美辛构象、生物活性和血清稳定性的作用，进行了构效关系（SAR）研究。最初，合成了缺乏一个或两个二硫键的戈美辛和变体。CD研究表明，戈美辛结构非常刚性，与溶剂环境无关。另一方面，线性化的类似物根据环境采用二级结构，而单环二硫键桥接的肽具有采用转角结构的趋势。一个或两个桥的情况下，导致在抗菌和溶血活性的下降。此外，血清稳定性研究表明，与甚至在孵育48小时后仍稳定的戈美辛相比，线性化类似物迅速降解。内酰胺桥取代二硫键导致单环和双环化合物。SAR研究表明，单环内酰胺桥连类似物倾向于呈现α-螺旋结构，其效力、溶血性和血清稳定性低于野生型戈美辛。另一方面，双环内酰胺/二硫键桥接类似物显示出与戈美辛相同的构象和降解动力学。然而，抗微生物活性似乎取决于内酰胺桥的位置和大小。这些发现表明（i）二级结构对戈美辛的全部活性起关键作用;（ii）戈美辛的抗微生物活性和溶血活性是相关的事件;（iii）虽然戈美辛的显著抗微生物活性需要至少一个二硫桥，但两个桥都是高血清稳定性和最佳构象所需的;最后（iv）获得的最佳类似物是双环（2- 15，6 -11）[Glu（2），Cys（6.11），Lys（15）]-Gm，因为它与戈美辛一样稳定和有效。(c)2005 Wiley Periodicals，Inc.
Gomesin is an antimicrobial peptide isolated from hemocytes of the Brazilian spider Acanthoscurria gomesiana that contains two disulfide bridges Cys(2-15)/Cys(6-11) and presents a beta-hairpin structure. To investigate the role of the disulfide bridges on gomesin conformation, bioactivities, and serum stability, structure-activity relationship (SAR) studies were conducted. Initially, gomesin and variants lacking one or both disulfide bridges were synthesized. CD studies showed that the gomesin structure is very rigid independently of the solvent enviromnent. On the other hand, the linearized analogues adopted secondary structures according to the environment, while the monocyclic disulfide-bridged peptides had a tendency to adopt a turn structure. The absence of one or both bridges resulted in a decrease in the antimicrobial and hemolytic activities. In addition, serum stability studies revealed that, contrasting to gomesin that was stable even after 48 h of incubation, the linearized analogues were rapidly degraded. The replacement of the disulfide bounds by lactam bridges led to monocyclic and bicyclic compounds. SAR studies indicated that the monocyclic lactam-bridged analogues tend to assume a alpha-helical structure being less potent, hemolytic, and serum stable than the wild-type gomesin. On the other hand, the bicyclic lactam/disulfide-bridged analogues displayed a similar conformation and degradation kinetics identical to gomesin. However, the antimicrobial activity appeared to be dependent on the lactam bridge position and size. These findings indicated that (i) the secondary structure plays a pivotal role for the full activity of gomesin; (ii) the antimicrobial and hemolytic activities of gomesin are correlated events; (iii) while at least one of the disulfide bridges is needed for the maintenance of a significant antimicrobial activity of gomesin, both bridges are required for high serum stability and optimal conformation; and finally (iv) the best analogue obtained was the bicyclo (2-15,6-11)[Glu(2), Cys(6.11), Lys(15) J-Gm since it is as stable and potent as gomesin. (c) 2005 Wiley Periodicals, Inc.