Pas H H, Meyer G H, Kruizinga W H, Tamminga K S, van Weeghel R P, Robillard G T
Department of Chemistry, Groningen, The Netherlands.
J Biol Chem. 1991 Apr 15;266(11):6690-2.
The mannitol-specific phosphotransferase system transport protein, Enzyme IIMtl, contains two catalytically important phosphorylated amino acid residues, both present on the cytoplasmic part of the enzyme. Recently, this portion has been subcloned, purified, and shown to be an enzymatically active domain. The N-terminal half has also been subcloned and shown to be the mannitol-binding domain. When combined the two domains catalyze mannitol phosphorylation at the expense of phospho-HPr (van Weeghel, R. P., Meyer, G. H., Pas, H. H., Keck, W. H., and Robillard, G. T., Biochemistry in press). The phospho-NMR spectrum of the purified phosphorylated cytoplasmic domain, taken at pH 8.0, shows two signals, one at -6.9 ppm compared with inorganic phosphate resulting from phosphohistidine and one at +11.9 ppm originating from phosphocysteine. Addition of mannitol plus membranes containing the N-terminal mannitol-binding domain results in the formation of mannitol 1-phosphate and the disappearance of the two signals at -6.9 and +11.9 ppm.
甘露醇特异性磷酸转移酶系统转运蛋白（酶IIMtl）含有两个具有催化重要性的磷酸化氨基酸残基，二者均位于该酶的细胞质部分。最近，这一部分已被亚克隆、纯化，并显示为一个具有酶活性的结构域。N端的一半也已被亚克隆，并显示为甘露醇结合结构域。当这两个结构域结合时，它们以磷酸化组氨酸蛋白（HPr）为代价催化甘露醇磷酸化（范·韦赫尔，R.P.，迈耶，G.H.，帕斯，H.H.，凯克，W.H.，以及罗比拉德，G.T.，《生物化学》即将发表）。在pH 8.0条件下测得的纯化的磷酸化细胞质结构域的磷核磁共振谱显示有两个信号，一个在-6.9 ppm处，与来自磷酸组氨酸的无机磷酸盐相比，另一个在+11.9 ppm处，源自磷酸半胱氨酸。加入甘露醇以及含有N端甘露醇结合结构域的膜会导致形成1-磷酸甘露醇，并且-6.9和+11.9 ppm处的两个信号消失。
