Hofmann O M, Mould R M, Brittain T
Department of Biochemistry, University of Auckland, New Zealand.
Protein Eng. 1994 Feb;7(2):281-3.
The production of adult human haemoglobin in a yeast expression system has been shown to lead to the formation of functional oxygen-binding tetrameric proteins with the incorporation of endogenously synthesized haem. Adachi et al. [(1992) Protein Engng, 5, 807-810] identified two partially resolvable forms of the expressed haemoglobin, one of which showed higher oxygen affinity and lower cooperativity than normal. We show that in contrast to the previously expressed view that the abnormal form is due to abnormal protein folding, that it represents tetrameric haemoglobin containing incorporated sulphaem. Furthermore, the incorporation of sulphaem is shown to be a time-dependent process, with no detectable sulphaem being incorporated prior to 16 h post-induction. Numerical simulation based on our analysis of sulphaem composition gives an excellent fit to oxygen binding data previously reported for samples containing mixtures of normal haemoglobin and sulphaemoglobin.
在酵母表达系统中生产成人血红蛋白已被证明会导致功能性氧结合四聚体蛋白的形成，并掺入内源性合成的血红素。安达奇等人[（1992年）《蛋白质工程》，5，807 - 810]鉴定出两种部分可分辨的表达血红蛋白形式，其中一种显示出比正常情况更高的氧亲和力和更低的协同性。我们表明，与之前表达的观点（即异常形式是由于蛋白质折叠异常）相反，它代表含有掺入硫血红蛋白的四聚体血红蛋白。此外，硫血红蛋白的掺入被证明是一个时间依赖性过程，在诱导后16小时之前没有可检测到的硫血红蛋白掺入。基于我们对硫血红蛋白组成的分析进行的数值模拟，与先前报道的含有正常血红蛋白和硫血红蛋白混合物的样品的氧结合数据非常吻合。
