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Structural basis for adenylation and thioester bond formation in the ubiquitin E1

Version 2 2024-06-19, 19:11
Version 1 2023-05-26, 01:34
journal contribution
posted on 2024-06-19, 19:11 authored by Zachary S Hann, Cheng Ji, Shaun K Olsen, Xuequan Lu, Michaelyn C Lux, Derek S Tan, Christopher D Lima
The ubiquitin (Ub) and Ub-like (Ubl) protein-conjugation cascade is initiated by E1 enzymes that catalyze Ub/Ubl activation through C-terminal adenylation, thioester bond formation with an E1 catalytic cysteine, and thioester bond transfer to Ub/Ubl E2 conjugating enzymes. Each of these reactions is accompanied by conformational changes of the E1 domain that contains the catalytic cysteine (Cys domain). Open conformations of the Cys domain are associated with adenylation and thioester transfer to E2s, while a closed conformation is associated with pyrophosphate release and thioester bond formation. Several structures are available for Ub E1s, but none has been reported in the open state before pyrophosphate release or in the closed state. Here, we describe the structures of Schizosaccharomyces pombe Ub E1 in these two states, captured using semisynthetic Ub probes. In the first, with a Ub-adenylate mimetic (Ub-AMSN) bound, the E1 is in an open conformation before release of pyrophosphate. In the second, with a Ub-vinylsulfonamide (Ub-AVSN) bound covalently to the catalytic cysteine, the E1 is in a closed conformation required for thioester bond formation. These structures provide further insight into Ub E1 adenylation and thioester bond formation. Conformational changes that accompany Cys-domain rotation are conserved for SUMO and Ub E1s, but changes in Ub E1 involve additional surfaces as mutational and biochemical analysis of residues within these surfaces alter Ub E1 activities.

History

Journal

Proceedings of the National Academy of Sciences of USA

Volume

116

Pagination

15475-15484

Location

Washington, D.C.

ISSN

0027-8424

eISSN

1091-6490

Language

English

Publication classification

C1.1 Refereed article in a scholarly journal

Issue

31

Publisher

National Academy of Sciences