Localization of basic residues required for receptor binding to the single α‐helix of the receptor binding domain of human α2‐macroglobulin

摘要: To better understand the structural basis for binding of proteinase-transformed human alpha2-macroglobulin (alpha2M) to its receptor, we have used three-dimensional multinuclear NMR spectroscopy determine secondary structure receptor domain (RBD) alpha2M. Assignment backbone resonances RBD was made using 13C/15-N and 15N-enriched expressed in Escherichia coli. The determined 1H 13C chemical shift indices inter- intrachain nuclear Overhauser enhancements. consists eight strands beta-conformation one alpha-helix, which together comprise 44% protein. beta-strands form three regions antiparallel beta-sheet. two lysines previously identified as being critical are located (Lys1374), immediately adjacent (Lys1370) also contains an (Arg1378). Secondary predictions other alpha-macroglobulins show conservation this alpha-helix suggest important role helix basic residues within it binding.