Conformational studies on the N‐linked carbohydrate chain of bromelain

Abstract

1H‐ and 13C‐NMR assignments for the carbohydrate part of the glycopeptide α‐d‐Man‐(1→6)‐[ß‐d‐Xyl‐(1→2)]‐ß‐d‐Man‐(1→4)‐ß‐d‐GlcNAc‐(1→4)‐[α‐l‐Fuc‐(1→3)]‐ß‐d‐ GlcNAc‐(1→N)‐Asn∼, derived from the proteolytic enzyme bromelain (EC 3.4.22.4), have been obtained using homo‐ and heteronuclear correlation spectroscopy, two‐dimensional homonuclear Hartmann‐Hahn and nuclear Overhauser enhancement experiments. A conformational model for the carbohydrate chain, deduced from the NMR data and consistent with hard‐sphere exo‐anomeric calculations shows that the rotamer population about the C‐5–C‐6 bond of ß‐Man is restricted to the Pω=180 rotamer, mainly. Copyright © 1990, Wiley Blackwell. All rights reserved