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Characterising side chains in large proteins by protonless ¹³C-detected NMR spectroscopy.

ABSTRACT: Side chains cover protein surfaces and are fundamental to processes as diverse as substrate recognition, protein folding and enzyme catalysis. However, characterisation of side-chain motions has so far been restricted to small proteins and methyl-bearing side chains. Here we present a class of methods, based on ¹³C-detected NMR spectroscopy, to more generally quantify motions and interactions of side chains in medium-to-large proteins. A single, uniformly isotopically labelled sample is sufficient to characterise the side chains of six different amino acid types. Side-chain conformational dynamics on the millisecond time-scale can be quantified by incorporating chemical exchange saturation transfer (CEST) into the presented methods, whilst long-range ¹³C-¹³C scalar couplings reporting on nanosecond to millisecond motions can be quantified in proteins as large as 80?kDa. The presented class of methods promises characterisation of side-chain behaviour at a level that has so far been reserved for the protein backbone.

SUBMITTER: Pritchard RB

PROVIDER: S-EPMC6465260 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature

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