两种人源肌动蛋白结合蛋白同工型的独特生化特性。

Distinct biochemical characteristics of the two human profilin isoforms.

作者信息

Gieselmann R, Kwiatkowski D J, Janmey P A, Witke W

机构信息

Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.

出版信息

Eur J Biochem. 1995 May 1;229(3):621-8. doi: 10.1111/j.1432-1033.1995.tb20506.x.

DOI:10.1111/j.1432-1033.1995.tb20506.x

PMID:7758455

Abstract

The biochemical characteristics of a new human profilin isoform are described. We refer to this recently described isoform as profilin II (isoelectric point 5.9) in comparison to profilin I (pI 8.4). We expressed both isoforms in bacteria and compared their actin-binding properties, binding to poly(L-proline), affinities for phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], and their effects on nucleotide exchange on actin. Profilin I and profilin II have similar affinities for PtdIns(4,5)P2 and poly(L-proline), and both accelerate nucleotide exchange on monomeric actin to the same extent. However, the affinity of profilin I for monomeric actin is about five times higher than the affinity of profilin II for actin. Potential structural differences of profilin I and profilin II that might explain the difference in actin binding are discussed.

摘要

本文描述了一种新的人源肌动蛋白结合蛋白亚型的生化特性。与肌动蛋白结合蛋白I（pI 8.4）相比，我们将这种最近描述的亚型称为肌动蛋白结合蛋白II（等电点5.9）。我们在细菌中表达了这两种亚型，并比较了它们的肌动蛋白结合特性、与聚（L-脯氨酸）的结合、对磷脂酰肌醇4,5-二磷酸[PtdIns(4,5)P2]的亲和力，以及它们对肌动蛋白上核苷酸交换的影响。肌动蛋白结合蛋白I和肌动蛋白结合蛋白II对PtdIns(4,5)P2和聚（L-脯氨酸）具有相似的亲和力，并且两者都能同等程度地加速单体肌动蛋白上的核苷酸交换。然而，肌动蛋白结合蛋白I对单体肌动蛋白的亲和力比对肌动蛋白结合蛋白II对肌动蛋白的亲和力高约五倍。文中讨论了肌动蛋白结合蛋白I和肌动蛋白结合蛋白II可能解释肌动蛋白结合差异的潜在结构差异。