Human α2‐macroglobulin structure

FEBS Letters

Gettins, Peter G.W.¹  Crews, Brenda C.¹ 

[1] Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA

关键词: α2-Macroglobulin;    Fluorescence resonance energy transfer;    Thiol ester;    Structure;    α2M;    α2-macroglobulin;    I-form α2M;    intermediate form α2-macroglobulin;    HEPES;    N-2-hydroxyethylpiperazine-N'-ethanesulfonic acid;    EDTA;    ethylenediaminetetraacetic acid;    5-IAF;    5-iodoacetamidofluorescein;    1;    5-I-AEDANS;    5[[2-[(iodoacetyl)amino]ethane]amino] naphthalene-1-sulfonate. PMSF;    phenylmethanesulfonyl fluoride;   

DOI  :  10.1016/0014-5793(93)80633-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

To localize the pair of thiol-ester-derived cysteine-949 residues within a half-molecule of α₂M and estimate the internal diameter of this α₂-macroglobulin trap, we have measured the separation between these cysteines. We unexpectedly found that the two cysteines of intermediate form α₂M had different reactivity, which permitted selective modification of one cysteine with dansyl, and the other with fluorescein fluorophores. From fluorescence energy transfer measurements, we calculated a separation of 41 ± 10 Å between these fluorophores. This indicates that the Cys-949 residues are probably located at the perimeter of the trap with an internal diameter at least as large as this separation.

【 授权许可】

Unknown