Determination of the Crystal Structure of Human Zn-Alpha 2-Glycoprotein, A Protein Implicated in Breast Cancer

摘要

Zn-alpha- 2-glycoprotein (ZAG) is a soluble protein that is present in serum and other body fluids. In addition, ZAG accumulates in breast cysts as well as in 40% of breast carcinomas. ZAG stimulates lipid degradation in adipocytes and causes the extensive fat losses associated with some advanced cancers. The 2.8 Angstrom crystal structure of ZAG resembles a class I major histocompatibility complex (MHC) heavy chain, but ZAG does not bind the class I light chain beta-2-microglobulin. The ZAG structure includes a large groove analogous to class I MHC peptide binding grooves. Instead of a peptide, the ZAG groove contains a non-peptidic compound that may be implicated in lipid catabolism under normal or pathological conditions.