Conformational studies by NMR of the antimicrobial peptide, drosocin, and its non-glycosylated derivative: effects of glycosylation on solution conformation.
Conformational studies by NMR of the antimicrobial peptide, drosocin, and its non-glycosylated derivative: effects of glycosylation on solution conformation.
复制标题
通过 NMR 对抗菌肽、卓索辛及其非糖基化衍生物进行构象研究：糖基化对溶液构象的影响。
DOI：
10.1021/bi981956d
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Craik,DJ
中科院分区：
文献类型：
--
作者：
McManus,AM;OtvosJr,L;Hoffmann,R;Craik,DJ
促红细胞生成素是一种由19个氨基酸组成的阳离子肽，是果蝇对脓毒性损伤的反应。该序列（GKPRPYSPRPTSHPRPIRV）包含6个Pro残基和4个Arg残基，它们被合并成3个重复的三重序列Pro-Arg-Pro。该肽在Thr11位点糖基化，具有有效的抗菌活性。这种活性在去糖基化过程中显著降低，但其结构基础此前尚未建立。在本研究中，通过核磁共振波谱和结构计算确定了红豆杉及其非糖基化衍生物的溶液构象。核磁共振和结构研究表明，肽在水溶液中具有显著的基本随机线圈构象。添加50%的三氟乙醇会导致小群折叠构象的形成，主要以旋转的形式出现。特别是，匝元出现在残数4−7、10−13、17和18附近。在糖基化和非糖基化形式的主要随机线圈构象中没有发现实质性差异，但在折叠构象的小种群中存在细微差异。特别是，在糖基化过程中，残基10−13的转向趋向于更延伸的结构，而在残基17和18的下游转向有一些收紧。糖段和糖基化位点附近的肽之间存在大量的核Overhauser增强接触，这与它们之间的密切联系一致。尽管这种密切的联系，pKaof H13，其接近糖基化位点，被发现不受糖基化的影响。
Drosocin is a cationic 19 amino acid peptide secreted byDrosophilain response to septic injury. The sequence (GKPRPYSPRPTSHPRPIRV) contains six Pro and four Arg residues which are incorporated into three repeated triplet sequences Pro-Arg-Pro. The peptide is glycosylated at Thr11 and has potent antimicrobial activity. This activity is markedly reduced on deglycosylation, but a structural basis for this has not been previously established. In the current study, the solution conformations of drosocin and its non-glycosylated derivative were determined by NMR spectroscopy and structure calculations. The NMR and structure studies showed that the peptides have significant populations of essentially random coil conformations in aqueous solution. Addition of 50% trifluoroethanol causes the development of small populations of folded conformations, mainly in the form of turns. In particular, turn elements occur near residues 4−7, 10−13, 17, and 18. No substantial difference was detected in the predominantly random coil conformation of the glycosylated and non-glycosylated forms, but there are subtle differences in the small populations of folded conformers. In particular, the turn at residues 10−13 tends toward a more extended structure on glycosylation, while there is some tightening of the downstream turn at residues 17 and 18. There are a significant number of nuclear Overhauser enhancement contacts between the sugar moiety and the peptide near the glycosylation site, consistent with a close association between them. Despite this close association, the pKaof H13, which is proximate to the glycosylation site, was found to be unaffected by glycosylation.