BCMB20002 Lecture Notes - Lecture 8: Pyruvate Dehydrogenase, Alpha Helix, Immunoglobulin Heavy Chain
Document Summary
All figures from lecture 8 slides of t. mulhern, melbourne university, march 2017 (unless stated) Only when there are multiple polypeptides, e. g. haemoglobin = 4 different polypeptides. The general term for a multimeric protein that consists of a small number of subunits is (cid:862)oligo(cid:373)e(cid:396)(cid:863). Homo = same subunits, hetero = not same. Haemoglobin can be described as a tetramer of four subunits or, more correctly, a dimer of two alpha-beta (cid:862)p(cid:396)oto(cid:373)e(cid:396)s(cid:863) A protomer is the stru(cid:272)tu(cid:396)al (cid:858)u(cid:374)it(cid:859) of a p(cid:396)otei(cid:374) (cid:449)ith a (cid:395)uate(cid:396)(cid:374)a(cid:396)(cid:455) st(cid:396)u(cid:272)tu(cid:396)e. Haemoglobin has taken the shape of a globin fold: 25% sequence identity. Each subunit can be subdivided in to functional regions or domains. In haemoglobin, each chain consists of a single globin domain. Immunoglobin gs (iggs) are proteins that consist of four subunits: 2 heavy chains and 2 light chain (light blue), both involved in binding to the antigen ligand. The variable regions at the end of each chain undergo conformational chain when they bind antigen.