Giordano Daniela, Boechi Leonardo, Vergara Alessandro, Martí Marcelo A, Samuni Uri, Dantsker David, Grassi Luigi, Estrin Darío A, Friedman Joel M, Mazzarella Lelio, di Prisco Guido, Verde Cinzia
Institute of Protein Biochemistry, National Research Council (CNR), Naples, Italy.
FEBS J. 2009 Apr;276(8):2266-77. doi: 10.1111/j.1742-4658.2009.06954.x. Epub 2009 Mar 9.
The dominant perciform suborder Notothenioidei is an excellent study group for assessing the evolution and functional importance of biochemical adaptations to temperature. The availability of notothenioid taxa in a wide range of latitudes (Antarctic and non-Antarctic) provides a tool to enable identification of physiological and biochemical characteristics gained and lost during evolutionary history. Non-Antarctic notothenioids belonging to the most basal families are a crucial source for understanding the evolution of hemoglobin in high-Antarctic cold-adapted fish. This paper focuses on the structure, function and evolution of the oxygen-transport system of Cottoperca gobio, a sub-Antarctic notothenioid fish of the family Bovichtidae, probably derived from ancestral species that evolved in the Antarctic region and later migrated to lower latitudes. Unlike most high-Antarctic notothenioids, but similar to many other acanthomorph teleosts, C. gobio has two major hemoglobins having the beta chain in common. The oxygen-binding equilibria and kinetics of the two hemoglobins have been measured. Hb1 and Hb2 show strong modulation of oxygen-binding equilibria and kinetics by heterotropic effectors, with marked Bohr and Root effects. In Hb1 and Hb2, oxygen affinity and subunit cooperativity are slightly higher than in most high-Antarctic notothenioid hemoglobins. Hb1 and Hb2 show similar rebinding rates, but also show significant dynamic differences that are likely to have functional consequences. Molecular dynamic simulations of C. gobio Hb1 were performed on the dimeric protein in order to obtain a better understanding of the molecular basis of structure/function relationships.
占主导地位的鲈形亚目南极鱼亚目是评估生物化学适应温度的进化及其功能重要性的绝佳研究群体。广泛纬度范围内（南极和非南极）都有南极鱼亚目分类群，这提供了一种工具，有助于识别在进化历史中获得和丧失的生理及生化特征。属于最原始科的非南极南极鱼亚目鱼类是了解高南极冷适应鱼类血红蛋白进化的关键来源。本文聚焦于南极牛鱼（Bovichtidae科的一种亚南极南极鱼亚目鱼类）氧运输系统的结构、功能和进化，这种鱼可能源自南极地区进化并随后迁移到低纬度地区的祖先物种。与大多数高南极南极鱼亚目鱼类不同，但与许多其他棘鳍类硬骨鱼相似，南极牛鱼有两种主要血红蛋白，它们有共同的β链。已测量了这两种血红蛋白的氧结合平衡和动力学。Hb1和Hb2表现出由异源效应物对氧结合平衡和动力学的强烈调节，具有显著的玻尔效应和鲁特效应。在Hb1和Hb2中，氧亲和力和亚基协同性略高于大多数高南极南极鱼亚目血红蛋白。Hb1和Hb2表现出相似的再结合速率，但也表现出可能具有功能后果的显著动态差异。为了更好地理解结构/功能关系的分子基础，对南极牛鱼Hb1的二聚体蛋白进行了分子动力学模拟。
