Bioinformatics approaches to the structure and function of intrinsically disordered proteins

Abstract

Intrinsically disordered proteins (IDPs) exist and function without well defined structures, which demands the structure-function paradigm be reassessed. Evidence is mounting that they carry out important functions in signal transduction and regulation of transcription, primarily in eukaryotes. By a battery of biophysical techniques, the structural disorder of about 500 proteins has been demonstrated, and functional studies have provided the basis of classifying their functions into various schemes. Indirect evidence suggests that the occurrence of disorder is widespread, and several thousand proteins with significant disorder exist in the human proteome alone. To narrow the wide gap between known and anticipated IDPs, a range of bioinformatics algorithms have been developed, which can reliably predict the disordered state from amino acid sequence. Attempts have also been made to predict IDP functions, although with much less success. Due to their fast evolution, and reliance on short motifs for function, sequence clues for recognizing IDP functions are rather limited. In this chapter we give a brief survey of the IDP field, with particular focus on their functions and bioinformatics approaches developed for predicting their structure and function. Potential future directions of research are also suggested and discussed. © 2009 Springer Netherlands.