Stabilization of Type-I .beta.-Turn Conformations in Peptides Containing the NPNA-Repeat Motif of the Plasmodium falciparum Circumsporozoite Protein by Substituting Proline for (S)-.alpha.-Methylproline
摘要:
The immunologically dominant central portion of the circumsporozoite (CS) surface protein on the malaria parasite Plasmodium falciparum contains a large number of tandemly repeated NPNA tetrapeptide motifs. The preferred secondary structure of this repeat unit in aqueous solution has been investigated with the aid of the secondary structure-inducing amino acid (S)-alpha-methylproline (p(Me)). H-1-Nuclear magnetic resonance (NMR) and circular dichroism (CD) spectroscopy have been used to probe the structures of synthetic peptides containing one to three tetrapeptide NP(Me)NA units. The far-UV CD spectra of these peptides show more intense negative bands at 215 nm than do similar peptides based on the NPNA motif. This and the temperature dependence of the peptide amide chemical shifts, the pattern of NOE connectivities, and the magnitude of (3)J coupling constants, derived from one- and two-dimensional NMR spectra of Ac(NP(Me)NA)(3)-OH, provide strong evidence for stable turnlike structures. From NOE distance and dihedral angle restraints, structures consistent with the NMR parameters were calculated. These reveal a stable hydrogen-bonded type-I beta-turn conformation (most likely present at 70-80% population) within each NP(Me)NA motif, stabilized by the backbone C-alpha methylation. Side chain to backbone hydrogen bonds involving the side chain amide groups of both asparagine residues also appear to impart stabilization to the turn conformation. No regular repeating conformations were detected in the linker regions connecting each NP(Me)NA unit. Polyclonal antisera raised in rabbits against (NP(Me)NA)(3) recognized intact P. falciparum sporozoites in an immunofluorescence assay as efficiently as antisera raised against (NPNA)(3). This indicates that the type-I beta-turn detected in the P-Me-containing peptide is closely related to the immunologically dominant portion of the folded CS protein. An improved knowledge of the three-dimensional structure of this protein may be of value for the design of second-generation synthetic malaria vaccines.
Protecting groups for asparagine and glutamine in peptide synthesis
申请人:MILLIPORE CORPORATION
公开号:EP0292228A2
公开(公告)日:1988-11-23
Trialkoxybenzyl (Taob) protected asparagine and glutamine, a method of synthesis and a method of use are provided. The Taob protected Asn and Gln have the following formulae:
wherein Z is an alkyl group having from 1 to 10 carbon atoms; X and W are any α-protecting group which can be selectively removed while maintaining Taob intact; Y is H or any group sufficiently active or activatable to react with NH₂- or NH= to generate an amide bond; n is 1 for asparagine or 2 for glutamine. These derivatives are stable in solution, have good solubility in organic solvents and couple directly without side reactions.
提供了三烷氧基苄基(Taob)保护天冬酰胺和谷氨酰胺、合成方法和使用方法。三烷氧基苄基(Taob)保护的天冬酰胺和谷氨酰胺具有下式:
其中 Z 是具有 1 至 10 个碳原子的烷基;X 和 W 是任何可选择性去除同时保持 Taob 完整的 α 保护基团;Y 是 H 或任何具有足够活性或可活化的基团,可与 NH₂- 或 NH= 反应生成酰胺键;n 对天冬酰胺为 1,对谷氨酰胺为 2。这些衍生物在溶液中稳定,在有机溶剂中溶解性好,可直接耦合而不会产生副反应。
HUDSON, DEREK
作者:HUDSON, DEREK
DOI:——
日期:——
US4935536A
申请人:——
公开号:US4935536A
公开(公告)日:1990-06-19
Stabilization of Type-I .beta.-Turn Conformations in Peptides Containing the NPNA-Repeat Motif of the Plasmodium falciparum Circumsporozoite Protein by Substituting Proline for (S)-.alpha.-Methylproline
作者:Christian Bisang、Christoph Weber、Janice Inglis、Celia A. Schiffer、Wilfred F. van Gunsteren、Ilian Jelesarov、Hans. R. Bosshard、John A. Robinson
DOI:10.1021/ja00135a008
日期:1995.8
The immunologically dominant central portion of the circumsporozoite (CS) surface protein on the malaria parasite Plasmodium falciparum contains a large number of tandemly repeated NPNA tetrapeptide motifs. The preferred secondary structure of this repeat unit in aqueous solution has been investigated with the aid of the secondary structure-inducing amino acid (S)-alpha-methylproline (p(Me)). H-1-Nuclear magnetic resonance (NMR) and circular dichroism (CD) spectroscopy have been used to probe the structures of synthetic peptides containing one to three tetrapeptide NP(Me)NA units. The far-UV CD spectra of these peptides show more intense negative bands at 215 nm than do similar peptides based on the NPNA motif. This and the temperature dependence of the peptide amide chemical shifts, the pattern of NOE connectivities, and the magnitude of (3)J coupling constants, derived from one- and two-dimensional NMR spectra of Ac(NP(Me)NA)(3)-OH, provide strong evidence for stable turnlike structures. From NOE distance and dihedral angle restraints, structures consistent with the NMR parameters were calculated. These reveal a stable hydrogen-bonded type-I beta-turn conformation (most likely present at 70-80% population) within each NP(Me)NA motif, stabilized by the backbone C-alpha methylation. Side chain to backbone hydrogen bonds involving the side chain amide groups of both asparagine residues also appear to impart stabilization to the turn conformation. No regular repeating conformations were detected in the linker regions connecting each NP(Me)NA unit. Polyclonal antisera raised in rabbits against (NP(Me)NA)(3) recognized intact P. falciparum sporozoites in an immunofluorescence assay as efficiently as antisera raised against (NPNA)(3). This indicates that the type-I beta-turn detected in the P-Me-containing peptide is closely related to the immunologically dominant portion of the folded CS protein. An improved knowledge of the three-dimensional structure of this protein may be of value for the design of second-generation synthetic malaria vaccines.