NMR Spectroscopic Characterization of the C-Mannose Conformation in a Thrombospondin Repeat Using a Selective Labeling Approach.

Authors :: Jonker HRA
Saxena K
Shcherbakova A
Tiemann B
Bakker H
Schwalbe H
Source :: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2020 Nov 09; Vol. 59 (46), pp. 20659-20665. Date of Electronic Publication: 2020 Sep 03.
Publication Year :: 2020
Abstract: Despite the great interest in glycoproteins, structural information reporting on conformation and dynamics of the sugar moieties are limited. We present a new biochemical method to express proteins with glycans that are selectively labeled with NMR-active nuclei. We report on the incorporation of <superscript>13</superscript> C-labeled mannose in the C-mannosylated UNC-5 thrombospondin repeat. The conformational landscape of the C-mannose sugar puckers attached to tryptophan residues of UNC-5 is characterized by interconversion between the canonical <superscript>1</superscript> C <subscript>4</subscript> state and the B <subscript>03</subscript> / <superscript>1</superscript> S <subscript>3</subscript> state. This flexibility may be essential for protein folding and stabilization. We foresee that this versatile tool to produce proteins with selectively labeled C-mannose can be applied and adjusted to other systems and modifications and potentially paves a way to advance glycoprotein research by unravelling the dynamical and conformational properties of glycan structures and their interactions.<br /> (© 2020 The Authors. Published by Wiley-VCH GmbH.)

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