STRUCTURE OF PROTEIN-BOUND BILE PIGMENTS

具有共价结合的血红素和四吡咯假体基团的蛋白质是 存在于所有生物体中，并在电子传输中发挥重要作用， 光化学反应和代谢过程。然而，了解 这些假体基团的化学结构和立体化学 它们的多肽结合形式是非常不完整的。性格特点很好的 红藻和蓝藻的胆蛋白代表着丰富的 用于研究依附的结构和机制的材料 四聚吡咯假体组。已知有五种不同的四种角色 共价连接到各种胆蛋白的多肽链上，以及 只有一个案例严格建立了这种结构。上一首 研究四吡咯假体基团的方法涉及 使修复体基团从多肽上分离。这些研究 导致了对结构的包容和相互冲突的建议 多肽连接的胆红素。本研究将使用的方法包括 将结合蛋白降解为更简单的多肽-色素 胆林肽的天然共价键干扰及纯化 通过高效液相色谱等温和的程序。这个 然后直接确定纯化后的胆林肽的结构 无需通过高分辨率核磁共振进行进一步的化学操作，并支持 通过对合适的合成化合物的研究。百事可乐轴承 藻蓝胆素、藻红胆素和藻红胆素组 检查过了。胆林结构参数的初步研究 将在体内进行多肽的附着。将采取的方法是 这项调查所使用的方法对研究 翻译后引入的蛋白质结构的不寻常方面 修改。

Proteins with covalently bound heme and tetrapyrrole prosthetic groups are present in all organisms and have important roles in electron transport, photochemical reactions, and metabolic processes. However, knowledge of the chemical structure and stereochemistry of these prosthetic groups in their polypeptide-bound forms is very incomplete. The well-characterized biliproteins of red algae and cyanobacteria represent an abundant source of material for the study of the structure and mechanism of attachment of tetrapyrrole prosthetic groups. Five different tetrapyrroles are known to be covalently linked to the polypeptide chains of various biliproteins, and in only one case has the structure been rigorously established. Previous approaches to the study of the tetrapyrrole prosthetic groups have involved detachment of the prosthetic groups from the polypeptide. These studies have led to inclusive and conflicting proposals for the structure of polypeptide-linked bilins. The approach to be used in this study involves the degradation of conjugated proteins to simpler peptide-pigments without disturbing the native covalent linkages and purification of bilin peptides by mild procedures such as high performance liquid chromatography. The structures of the purified bilin-peptides will then be determined directly without further chemical manipulation by high resolution NMR and supported by studies on appropriate synthetic compounds. Peptdies bearing phycocyanobilin, phycoerythrobilin, and phycourobilin groups will be examined. Preliminary studies of the structural parameters governing bilin attachment to polypeptide in vivo will be conducted. The approach to be utilized in this investigation has general applicability to the study of unusual aspects of protein structure introduced by post-translational modification.