IMBB-FORTH, N. Plastira 100, Heraklion 70013, Greece.
J Pept Sci. 2012 Nov;18(11):678-84. doi: 10.1002/psc.2454. Epub 2012 Sep 28.
The atomic resolution structures of samarosporin I have been determined at 100 and 293 K. This is the first crystal structure of a natural 15-residue peptaibol. The amino acid sequence in samarosporin I is identical to emerimicin IV and stilbellin I. Samarosporin is a peptide antibiotic produced by the ascomycetous fungus Samarospora rostrup and belongs to peptaibol subfamily 2. The structures at both temperatures are very similar to each other adopting mainly a 3₁₀-helical and a minor fraction of α-helical conformation. The helices are significantly bent and packed in an antiparallel fashion in the centered monoclinic lattice leaving among them an approximately 10-Å channel extending along the crystallographic twofold axis. Only two ordered water molecules per peptide molecule were located in the channel. Comparisons have been carried out with crystal structures of subfamily 2 16-residue peptaibols antiamoebin and cephaibols. The repercussion of the structural analysis of samarosporin on membrane function is discussed.
已分别在 100 和 293 K 下确定了萨罗孢菌素 I 的原子分辨率结构。这是首个天然 15 残基缩肽的晶体结构。萨罗孢菌素 I 的氨基酸序列与埃默里霉素 IV 和斯蒂尔伯林 I 相同。萨罗孢菌素是一种由子囊菌真菌萨罗孢菌产生的肽类抗生素，属于缩肽亚家族 2。两种温度下的结构非常相似，主要采用 3₁₀-螺旋和少量α-螺旋构象。螺旋明显弯曲并以反平行方式包装在中心单斜晶格中，在它们之间留下一个大约 10-Å 的通道，沿晶体学的两倍轴延伸。每个肽分子中仅定位了两个有序水分子。与亚家族 2 的 16 残基缩肽抗阿米巴素和 Cephaibols 的晶体结构进行了比较。讨论了萨罗孢菌素结构分析对膜功能的影响。
