Donella A, Pinna L A, Moret V
Chem Biol Interact. 1976 Oct 2;15(2):165-71. doi: 10.1016/0009-2797(76)90161-7.
It has been suggested that the binding of iron(III) by phosvitin involves the phosphoric radicals of phosphorylserine residues, many of which are arranged in rows of several consecutive phosphoamino acids. In this paper we present evident that, unlike free phosphorylserine which does not interact with Fe(III), polyphosphorylserine blocks--(Ser-P)n, with n greater than or equal to 4 -- bind Fe(III) like phosvitin, though less actively, to give complexes stable at very acidic pHs. The binding of iron does not cause any polymerization of the phosphopeptides, and the (Ser-P)n-Fe(III) complexes display an Fe/P ratio significantly lower than 0.5, found in Fe-saturated phosvitin. These findings indicate that polyphosphorylserine blocks play an important role in the binding of iron by phosvitin, and that in the intact protein their binding capacity is optimized by the conformation of the polypeptide chain.
有人提出，卵黄高磷蛋白与铁（III）的结合涉及磷酸丝氨酸残基的磷酸基团，其中许多磷酸基团以几个连续的磷酸氨基酸排成行。在本文中，我们提供的证据表明，与不与铁（III）相互作用的游离磷酸丝氨酸不同，多聚磷酸丝氨酸嵌段（Ser-P）n（n大于或等于4）像卵黄高磷蛋白一样结合铁（III），尽管活性较低，能形成在非常酸性的pH值下稳定的复合物。铁的结合不会导致磷酸肽的任何聚合，并且（Ser-P）n-铁（III）复合物的铁/磷比率明显低于在铁饱和的卵黄高磷蛋白中发现的0.5。这些发现表明，多聚磷酸丝氨酸嵌段在卵黄高磷蛋白与铁的结合中起重要作用，并且在完整蛋白质中，它们的结合能力通过多肽链的构象得到优化。
