000168373 001__ 168373
000168373 005__ 20260204153543.0
000168373 0247_ $$2doi$$a10.1021/acscatal.5c07826
000168373 0248_ $$2sideral$$a147871
000168373 037__ $$aART-2025-147871
000168373 041__ $$aeng
000168373 100__ $$aSanz-Martínez, Ignacio$$uUniversidad de Zaragoza
000168373 245__ $$aFUT8 Catalysis Involves GDP-Fucose–Induced Loop Activation Promoting a Reaction at the SN1-SN2 Frontier
000168373 260__ $$c2025
000168373 5060_ $$aAccess copy available to the general public$$fUnrestricted
000168373 5203_ $$aα1,6-Fucosyltransferase 8 (FUT8) catalyzes the core α1,6-fucosylation of N-glycans, a modification essential for the biological function of many mammalian glycoproteins. Despite its importance, the structural and mechanistic aspects of FUT8 catalysis remain incompletely understood. Here, we combine molecular dynamics, QM/MM, and metadynamics simulations to delineate the full catalytic cycle of FUT8. We reveal that GDP-fucose binding induces a concerted conformational rearrangement of two flexible loops, which cooperatively stabilize a closed, catalytically competent active site. Formation of the Michaelis complex primes the enzyme for fucose transfer via a slightly late and highly asynchronous SN2 inverting mechanism. In fact, the reaction proceeds through a late transition state in a single kinetic step (energy barrier ∼18 kcal/mol, consistent with experimental kcat values) but in three different stages, i.e.: (i) cleavage of the glycosidic bond between fucose and GDP, (ii) formation of the glycosidic bond and (iii) H-transfer from the acceptor to the catalytic Glu373, underscoring the asynchronous nature of this process. Moreover, topological calculations of the electron localization function (ELF) along the reaction coordinate reveal the transient formation of an intimate ion pair, with a lifetime of 350–800 fs, as a transient intermediate; notably, despite the cationic character of the transition state, no stable intermediate is formed. These findings highlight how structural rearrangements enable a chemically distinct catalytic process and provide a structural framework for rational inhibitor design.
000168373 536__ $$9info:eu-repo/grantAgreement/ES/DGA/E34-20R$$9info:eu-repo/grantAgreement/ES/MICINN AEI/PID2022-136362NB-I00$$9info:eu-repo/grantAgreement/ES/MICINN/PID2022-137973NB-I00
000168373 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttps://creativecommons.org/licenses/by/4.0/deed.es
000168373 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000168373 700__ $$0(orcid)0000-0003-3433-6701$$aTejero, Tomás$$uUniversidad de Zaragoza
000168373 700__ $$0(orcid)0000-0002-3122-9401$$aHurtado-Guerrero, Ramón
000168373 700__ $$0(orcid)0000-0002-2202-3460$$aMerino, Pedro$$uUniversidad de Zaragoza
000168373 7102_ $$12013$$2765$$aUniversidad de Zaragoza$$bDpto. Química Orgánica$$cÁrea Química Orgánica
000168373 773__ $$g(2025), [13 pp.]$$pACS catal.$$tACS CATALYSIS$$x2155-5435
000168373 8564_ $$s10861872$$uhttps://zaguan.unizar.es/record/168373/files/texto_completo.pdf$$yVersión publicada
000168373 8564_ $$s3377485$$uhttps://zaguan.unizar.es/record/168373/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000168373 909CO $$ooai:zaguan.unizar.es:168373$$particulos$$pdriver
000168373 951__ $$a2026-02-04-13:14:44
000168373 980__ $$aARTICLE