Molecular discrimination of structurally equivalent Lys 63-linked and linear polyubiquitin chains

摘要

Overall, our analysis shows that Lys 63 and linear ubiquitin chains are virtually equivalent in overall conformation, and form a structure in which individual ubiquitin moieties can be regarded as singular units that are rotationally unrestrained and highly flexible. Nevertheless, remarkable differences in specificity exist between chain types. Differential recognition and hydrolysis by DUBs can be explained by the chemically distinct isopeptide Iysine linkage compared with the peptide linkage in linear chains Differential recognition by UBDs is more difficult to rationalize, and further structural work will provide new insights into the principles of specific ubiquitin chain recognition by UBDs.