Frey Alexander D, Kallio Pauli T
Institute of Biotechnology, ETH Zürich, 8093 Zürich, Switzerland.
FEMS Microbiol Rev. 2003 Oct;27(4):525-45. doi: 10.1016/S0168-6445(03)00056-1.
In response to oxygen limitation or oxidative and nitrosative stress, bacteria express three kinds of hemoglobin proteins: truncated hemoglobins (tr Hbs), hemoglobins (Hbs) and flavohemoglobins (flavo Hbs). The two latter groups share a high sequence homology and structural similarity in their globin domain. Flavohemoglobin proteins contain an additional reductase domain at their C-terminus and their expression is induced in the presence of reactive nitrogen and oxygen species. Flavohemoglobins detoxify NO in an aerobic process, termed nitric oxide dioxygenase reaction, which protects the host from various noxious nitrogen compounds. Only a small number of bacteria express hemoglobin proteins and the best studied of these is from Vitreoscilla sp. Vitreoscilla hemoglobin (VHb) has been expressed in various heterologous hosts under oxygen-limited conditions and has been shown to improve growth and productivity, rendering the protein interesting for biotechnology industry. The close interaction of VHb with the terminal oxidases has been shown and this interplay has been proposed to enhance respiratory activity and energy production by delivering oxygen, the ultimate result being an improvement in growth properties.
为应对氧气限制或氧化应激及亚硝化应激，细菌会表达三种血红蛋白蛋白：截短血红蛋白（tr Hbs）、血红蛋白（Hbs）和黄素血红蛋白（flavo Hbs）。后两组在其珠蛋白结构域具有高度的序列同源性和结构相似性。黄素血红蛋白蛋白在其C末端含有一个额外的还原酶结构域，并且在活性氮和氧存在的情况下其表达会被诱导。黄素血红蛋白在需氧过程中使一氧化氮解毒，这一过程称为一氧化氮双加氧酶反应，可保护宿主免受各种有害氮化合物的侵害。只有少数细菌表达血红蛋白蛋白，其中研究得最深入的来自透明颤菌属。透明颤菌血红蛋白（VHb）已在氧气受限条件下在各种异源宿主中表达，并已显示出可改善生长和提高生产力，这使得该蛋白对生物技术产业具有吸引力。VHb与末端氧化酶的密切相互作用已被证实，并且有人提出这种相互作用通过输送氧气来增强呼吸活性和能量产生，最终结果是改善生长特性。
