Cross-linking in adhesive quinoproteins: Studies with model decapeptides
Cross-linking in adhesive quinoproteins: Studies with model decapeptides
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DOI：
10.1021/bi0002434
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发表时间：
2000-09-12
期刊：
影响因子：
2.9
通讯作者：
Waite, JH
中科院分区：
文献类型：
--
作者：
Burzio, LA;Waite, JH
紫贻贝足蛋白-1（mefp 1）是贻贝足丝的主要组成部分，足丝是贻贝的一种粘附物质。最近关于足丝中5，5 ′-二（二羟基苯基-L-丙氨酸）（diDOPA）交联的报道[McDowell等（1999）J.Biol.Chem.274，20293]提出了关于这些与mefp 1的关系的问题。mefp 1的大约80%的一级结构由串联重复的共有序列Ala（1）-Lys（2）-Pro（3）-Ser（4）-Tyr（5）-Pro（6）-Pro（7）-Thr（8）-Tyr（9）-Lys（10）组成，在位置3、6和7处具有不同程度的翻译后羟基化为羟脯氨酸，在位置5和9处具有不同程度的翻译后羟基化为多巴。这十肽的六种天然或合成变体通过酪氨酸酶或高碘酸盐进行氧化。多巴是所有氧化肽中唯一遭受损失的残基。此外，使用MALDI TOF质谱法，氧化的十肽都显示出多聚体形成的证据和每对偶联肽的质量损失为6 Da。多聚体的形成被抑制通过添加DOPA样邻苯二酚，但添加简单的胺，如游离赖氨酸没有效果。结果与芳氧基偶联到二多巴，然后再氧化成二多巴醌一致。然而，在肽同源物之间的多聚体形成中存在微妙但值得注意的变化。Pro（3）修饰为反式-4-羟脯氨酸的十肽不会形成超过二聚体的多聚体;在多巴氧化后，它们也表现出显著的赖氨酸损失。此外，在Ala-Lys-Hyp-Ser-Tyr-DiHyp-Hyp-Thr-DOPA-Lys中，Tyr似乎被酪氨酸酶保护免于氧化。
Mytilus edulis foot protein-1 (mefp1) is a major component of the byssus, an adhesive holdfast in mussels. The recent report of 5,5'-di(dihydroxyphenyl-L-alanine) (diDOPA) cross-links in byssus [McDowell et al. (1999) J. Biol. Chem. 274, 20293] has raised questions about the relationship of these to mefp1. About 80% of the primary structure of mefp1 consists of a tandemly repeated consensus sequence Ala(1)-Lys(2)-Pro(3)-Ser(4)-Tyr(5)-Pro(6)-Pro(7)-Thr(8)-Tyr(9)-Lys(10) with varying degrees of posttranslational hydroxylation to hydroxyprolines in positions 3, 6, and 7 and to DOPA in positions 5 and 9. Six natural or synthetic variants of this decapeptide were subjected to oxidation by tyrosinase or periodate. DOPA is the only residue to suffer losses in all oxidized peptides. Moreover, using MALDI TOF mass spectrometry, oxidized decapeptides all showed evidence of multimer formation and a mass loss of 6 Da per coupled pair of peptides. Multimer formation was inhibited by addition of DOPA-like o-diphenols, but addition of simple amines such as free Lys had no effect. The results are consistent with aryloxy coupling to diDOPA followed by reoxidation to diDOPA quinone. There are subtle but noteworthy variations, however, in multimer formation among the peptide congeners. Decapeptides with Pro(3) modified to trans-4-hydroxyproline do not form multimers beyond dimers; they also exhibit significant Lys losses following oxidation of DOPA. Moreover, in Ala-Lys-Hyp-Ser-Tyr-DiHyp-Hyp-Thr-DOPA-Lys, Tyr appears to be protected from oxidation by tyrosinase.