Abstract
Shwachman-Diamond Syndrome (SDS) is an autosomal recessive disorder whose patients present mutations in two ribosome assembly proteins, the Shwachman-Bodian-Diamond Syndrome protein (SBDS) and the Elongation Factor-Like 1 (EFL1). Due to the lack of knowledge of the molecular mechanisms responsible for SDS pathogenesis, current therapy is nonspecific and focuses only at alleviating the symptoms. Building on the recent observation that EFL1 single-point mutations clinically manifest as SDS-like phenotype, we carried out comparative Molecular Dynamics (MD) simulations on three mutants, T127A, M882K and R1095Q and wild type EFL1. As supported by small angle X-ray scattering experiments, the obtained data improve the static EFL1 model resulting from the Cryo-electron microscopy and clearly show that all the mutants experience a peculiar rotation, around the hinge region, of domain IV with respect to domains I and II leading to a different conformation respect to that of wild type protein. This study supports the notion that EFL1 function is governed by an allosteric mechanism involving the concerted action of GTPase domain (domain I) and the domain IV and can help point towards new approaches to SDS treatment.
Communicated by Ramaswamy H. Sarma
Disclosure statement
Authors declare no potential conflict of interest.
Acknowledgements
We acknowledge the CINECA awards no. HP10CK8QNI-SdsEFL1 under the ISCRA initiative for the availability of high-performance computing resources; the CNCCS Consortium Project “Collezione di Composti Chimici ed attività di screening” for financial support and CONACYT project 283909. SAXS experiments were carried out at beamline B21 at the Diamond Light Source, (United Kingdom) under the project MX21741-1 (Italian BAG project). We thank Nathan Cowieson (Diamond, UK) for the assistance in using the B21 beamline and initial data analysis.