Department of Pathology, Haartman Institute, University of Helsinki and HUSLAB, PO Box 21, Haartmaninkatu 3, FI-00014 Helsinki, Finland.
Biochem Biophys Res Commun. 2011 Jun 3;409(2):266-9. doi: 10.1016/j.bbrc.2011.05.002. Epub 2011 May 6.
Hemin (iron protoporphyrin IX) is a necessary component of many proteins, functioning either as a cofactor or an intracellular messenger. Hemoproteins have diverse functions, such as transportation of gases, gas detection, chemical catalysis and electron transfer. Stanniocalcin 1 (STC1) is a protein involved in respiratory responses of the cell but whose mechanism of action is still undetermined. We examined the ability of STC1 to bind hemin in both its reduced and oxidized states and located Cys(114) as the axial ligand of the central iron atom of hemin. The amino acid sequence differs from the established (Cys-Pro) heme regulatory motif (HRM) and therefore presents a novel heme binding motif (Cys-Ser). A STC1 peptide containing the heme binding sequence was able to inhibit both spontaneous and H(2)O(2) induced decay of hemin. Binding of hemin does not affect the mitochondrial localization of STC1.
血红素（铁原卟啉 IX）是许多蛋白质的必需组成部分，它可以作为辅助因子或细胞内信使发挥作用。血红素蛋白具有多种功能，如气体运输、气体检测、化学催化和电子转移。Stanniocalcin 1（STC1）是一种参与细胞呼吸反应的蛋白质，但作用机制尚不清楚。我们研究了 STC1 在还原态和氧化态下结合血红素的能力，并确定 Cys（114）为血红素中心铁原子的轴向配体。该氨基酸序列与已建立的（Cys-Pro）血红素调节基序（HRM）不同，因此呈现出一种新的血红素结合基序（Cys-Ser）。含有血红素结合序列的 STC1 肽能够抑制血红素的自发和 H2O2 诱导的衰减。血红素的结合并不影响 STC1 的线粒体定位。
