STRUCTURAL REQUIREMENTS OF N-GLYCOSYLATION OF PROTEINS - STUDIES WITH PROLINE PEPTIDES AS CONFORMATIONAL PROBES
STRUCTURAL REQUIREMENTS OF N-GLYCOSYLATION OF PROTEINS - STUDIES WITH PROLINE PEPTIDES AS CONFORMATIONAL PROBES
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DOI：
10.1042/bj2090331
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发表时间：
1983-01-01
影响因子：
4.1
通讯作者：
BAUSE, E
中科院分区：
文献类型：
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作者：
BAUSE, E
用一系列含脯氨酸的肽作为分子探针，研究了N-糖基化的构象方面。取决于亚氨基酸在肽链中的位置，产生糖基化速率的显著改变，指出构建标记序列三联体Asn-Xaa-Thr（Ser）的氨基酸对潜在糖连接位点的形成的关键贡献。对于在位置Xaa或在C-末端侧的Asn-序列子的苏氨酸之外的下一位置中含有脯氨酸残基的那些肽，根本没有糖基转移，而六肽Pro-Asn-Gly-Thr-Ala-Val以高速率糖基化。（粗体残基表示在所有肽中相同的标记序列，斜体残基区分脯氨酸在各种肽中的位置）。利用空间填充模型的研究表明，Ala（Pro）-Asn-Gly-Thr-Pro-瓦尔的糖基受体能力的缺乏可能与它们不能采用和/或稳定允许标记序列内的羟基氨基酸和天冬酰胺残基之间的催化必需相互作用的转角或环构象直接相关。这一结论是支持的圆二色光谱数据，这表明在这种类型的非受体肽的结构形成的潜力占主导地位的那些有利于诱导一个适当的糖连接位点的受体肽。Tyr-Asn-Pro-Thr-Ser-Val缺乏受体性质表明，即使是识别模式中的小修饰也不能被N-糖基转移酶所耐受。
Conformational aspects of N-glycosylation were investigated with a series of proline-containing peptides as molecular probes. Depending on the position of the imino acid in the peptide chain, dramatic alterations of glycosylation rates are produced, pointing to a critical contribution of the amino acids framing the marker sequence triplet Asn-Xaa-Thr(Ser) on the formation of a potential sugar-attachment site. No glycosyl transfer at all was detectable to those peptides containing a proline residue either in position Xaa or in the next position beyond the threonine of the Asn-sequon on the C-terminal side, whereas the hexapeptide Pro-Asn-Gly-Thr-Ala-Val was glycoslyated at a high rate. (Boldfaced residues denote the marker sequence that is identical in all the peptides, italicized residues distinguish the positions of proline in the various peptides). Studies with space-filling models reveal that the lack of glycosyl-acceptor capabilities of Ala(Pro)-Asn-Gly-Thr-Pro-Val might be directly related to their inability to adopt and/or stabilize a turn or loop conformation which permits the catalytically essential interaction between the hydroxy amino acid and the asparagine residue within the marker sequence. This conclusion is supported by circular-dichroism spectroscopic data, which suggest structure-forming potentials in this type of non-acceptor peptides dominating over those that favor the induction of an appropriate sugar-attachment site in the acceptor peptides. The lack of acceptor properties of Tyr-Asn-Pro-Thr-Ser-Val indicates that even small modifications in the recognition pattern are not tolerated by the N-glycosyltransferases.