NMR SOLUTION STRUCTURE AND FLEXIBILITY OF A PEPTIDE ANTIGEN REPRESENTING THE RECEPTOR-BINDING DOMAIN OF PSEUDOMONAS-AERUGINOSA
NMR SOLUTION STRUCTURE AND FLEXIBILITY OF A PEPTIDE ANTIGEN REPRESENTING THE RECEPTOR-BINDING DOMAIN OF PSEUDOMONAS-AERUGINOSA
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DOI：
10.1021/bi00212a008
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发表时间：
1993-12-14
期刊：
影响因子：
2.9
通讯作者：
SYKES, BD
中科院分区：
文献类型：
--
作者：
MCINNES, C;SONNICHSEN, FD;SYKES, BD
用一维和二维核磁共振技术研究了铜绿假单胞菌K株菌毛蛋白C-末端的合成肽抗原。该肽以两种异构体形式存在，其由I138-P139酰胺键产生。使用模拟退火程序结合来自NMR数据的距离和扭转角限制，已生成的17个残基的二硫键桥接肽（PAK 128-144）的反式的溶液构象的合奏。已经鉴定了这种潜在的合成疫苗的一种主要的骨架构象类型，并且表明在区域134-142中存在两个β-转角。已被确立为单克隆抗体PK 99 H的表位的区域与在系综中表现出最清晰的主要构象异构体的区域一致（134 -140），并且还包括从残基134至137的I型β-转角。生成的结构也与观察到的β-转角和酰胺质子温度系数数据的NOE特征一致，这表明在残基134和142之间存在两个转角。表位内二级结构的存在证实了蛋白质的免疫原性区域是含有表面暴露的结构元件如β-转角的那些的理论。对抗原性和交叉反应性的结构的进一步影响进行了讨论。
A synthetic peptide antigen corresponding to the C-terminus of Pseudomonas aeruginosa K strain pilin has been studied by one and two-dimensional NMR techniques. This peptide exists in two isomeric forms which arise as a result of the I138-P139 amide bond. An ensemble of solution conformations for the trans form of this 17-residue disulfide-bridged peptide (PAK 128-144) has been generated using a simulated annealing procedure in conjunction with distance and torsion angle restraints derived from NMR data. One major class of backbone conformations has been identified for this potential synthetic vaccine and indicates the presence of two beta-turns in the region 134-142. The region that has been established as the epitope for the monoclonal antibody PK99H is consistent with the region of the major conformers that exhibit the most definition in the ensemble (1 34-140) and also includes a type I beta-turn from residues 134 to 137. The generated structures are also consistent with observed NOEs characteristic of beta-turns and amide proton temperature coefficient data, which indicate the presence of two turns between residues 134 and 142. The presence of secondary structure within the epitope substantiates the theory that immunogenic regions of proteins are those which contain surface-exposed structural elements such as beta-turns. Further implications of the structure on antigenicity and cross-reactivity are discussed.