Crystallographic and NMR evidence for flexibility in oligosaccharyltransferases and its catalytic significance

James Nyirenda, Shunsuke Matsumoto, Takashi Saitoh, Nobuo Maita, Nobuo N. Noda, Fuyuhiko Inagaki, Daisuke Kohda

    Research output: Contribution to journalArticle

    19 Citations (Scopus)

    Abstract

    Oligosaccharyltransferase (OST) is a membrane-bound enzyme that catalyzes the transfer of an oligosaccharide to an asparagine residue in glycoproteins. It possesses a binding pocket that recognizes Ser and Thr residues at the +2 position in the N-glycosylation consensus, Asn-X-Ser/Thr. We determined the crystal structures of the C-terminal globular domains of the catalytic subunits of two archaeal OSTs. A comparison with previously determined structures identified a segment with remarkable conformational plasticity, induced by crystal contact effects. We characterized its dynamic properties in solution by 15N NMR relaxation analyses. Intriguingly, the mobile region contains the +2 Ser/Thr-binding pocket. In agreement, the flexibility restriction forced by an engineered disulfide crosslink abolished the enzymatic activity, and its cleavage fully restored activity. These results suggest the necessity of multiple conformational states in the reaction. The dynamic nature of the Ser/Thr pocket could facilitate the efficient scanning of N-glycosylation sequons along nascent polypeptide chains.

    Original languageEnglish
    Pages (from-to)32-41
    Number of pages10
    JournalStructure
    Volume21
    Issue number1
    DOIs
    Publication statusPublished - Jan 8 2013

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    All Science Journal Classification (ASJC) codes

    • Structural Biology
    • Molecular Biology

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