Hourdez S, Lamontagne J, Peterson P, Weber R E, Fisher C R
Department of Biology, Pennsylvania State University, University Park, USA.
Biol Bull. 2000 Oct;199(2):95-9. doi: 10.2307/1542868.
Deep-sea hydrothermal-vent fauna live in a highly variable environment where oxygen levels can be very low, and carbon dioxide and sulfide can reach high concentrations (1). These conditions are harsh for most aerobic metazoans, yet copepods can be abundant at hydrothermal vents. Here we report the structure and functional properties of hemoglobin extracted from the copepod Benthoxynus spiculifer, which was found in large numbers in a paralvinellid/gastropod community collection made during a cruise to the Juan de Fuca Ridge in 1998. Although hemoglobin has been reported in some littoral copepods (2), this is the first study of the structure and functional properties of copepod hemoglobin. Hemoglobin represents about 60% of the total soluble proteins extracted from B. spiculifer, and although it imparts a red color to the copepod, it does not provide a significant storage pool of oxygen. It is a 208-kDa protein, composed of 14 globin chains--7 of 14.3 kDa and 7 of 15.2 kDa. The hemoglobin has a very high and temperature-sensitive oxygen affinity, with no cooperativity or Bohr effect. These properties are adaptive for an animal living in a low-oxygen environment in which the primary function of the hemoglobin is most likely oxygen acquisition to support aerobic respiration.
深海热液喷口动物群生活在一个高度多变的环境中，那里的氧气水平可能非常低，而二氧化碳和硫化物的浓度可能很高（1）。这些条件对大多数需氧后生动物来说很苛刻，但桡足类动物在热液喷口处却可能数量众多。在这里，我们报告了从桡足类动物尖刺底栖猛水蚤中提取的血红蛋白的结构和功能特性，该桡足类动物是在1998年前往胡安德富卡海岭的一次航行中，在一个以拟阿尔文虾/腹足动物为主的群落样本中大量发现的。尽管在一些沿海桡足类动物中已报道过血红蛋白（2），但这是首次对桡足类动物血红蛋白的结构和功能特性进行研究。血红蛋白约占从尖刺底栖猛水蚤中提取的总可溶性蛋白的60%，尽管它使桡足类动物呈现红色，但它并没有提供大量的氧气储存库。它是一种208千道尔顿的蛋白质，由14条珠蛋白链组成——7条14.3千道尔顿的和7条15.2千道尔顿的。这种血红蛋白具有非常高且对温度敏感的氧亲和力，没有协同性或波尔效应。这些特性对于生活在低氧环境中的动物具有适应性，在这种环境中，血红蛋白的主要功能很可能是获取氧气以支持有氧呼吸。
