Three-dimensional reconstruction of a complex of human alpha 2-macroglobulin with monomaleimido Nanogold (Au1.4nm) embedded in ice. |
| |
Authors: | N Boisset R Grassucci P Penczek E Delain F Pochon J Frank J N Lamy |
| |
Institution: | Laboratoire de Biochimie Fondamentale, Université Fran?ois Rabelais and CNRS URA 1334, Tours, France. |
| |
Abstract: | Cysteine 949 and glutamine 952 are known to be part of the thiol ester site of each of the four subunits of human alpha 2-macroglobulin (alpha 2M). The hydrolysis of this thiol ester bound to methylamine results in the incorporation of the amine and liberation of a free sulfhydryl group that can be specifically labeled. Therefore, a high-resolution marker specific for the sulfhydryl groups, the monomaleimido Nanogold (Au1.4nm) cluster was used to bind this amino acid. After cryoelectron microscopy, a three-dimensional reconstruction of the alpha 2M-Nanogold conjugates (alpha 2M-Au1.4nm) was achieved, revealing the internal location of the thiol ester sites in the transformed alpha 2M molecules. From this study we propose three possible locations for the cysteine 949. |
| |
Keywords: | |
|
|