Title:Effect of Disease Causing Missense Mutations on Intrinsically Disordered
Regions in Proteins
Volume: 29
Issue: 3
Author(s): Suryanarayana Seera and Hampapathalu A. Nagarajaram*
Affiliation:
- Department of Systems and Computational Biology, Laboratory of Computational
Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India
Keywords:
Conformational heterogeneity, Intrinsically disordered protein, intrinsically disordered region, molecular dynamics, conformation, disease causing mutation, missense mutation, energy landscape.
Abstract:
Introduction: Disease causing missense mutations (DCMMs) destabilize protein structures.
However it is not known how they impact the intrinsically disordered regions (IDRs) as these
regions do not adopt stable 3D structures under physiological conditions. It is therefore imperative
to investigate the effect of DCMMs on the functionally important IDRs.
Objective: To investigate impact of DCMMs on functionally important IDRs in human proteins.
Methods: We investigated the impact of the known DCMMs on three IDRs: a) an IDR with CRIB
motif from WAS protein , b) a proline rich IDR of p22 protein and c) an IDR horboring TRM motif
from SH3BP2 protein. Both the wild type and the mutant forms were subjected to detailed structural
investigations using MD simulations for 100ns.
Results: MD studies revealed that the mutants adopt fewer conformational states as compared with
their wild-type counterparts of which one or two form the dominant conformational states. This result
was also corroborated by the free-energy landscapes of the mutants with a fewer minima as
compared with the wild-types. It was also observed that the side chains of the mutated amino acid
residues introduce new hydrogen bonding interactions that stabilize one or two of the dominant conformational
states.
Conclusion: Our studies, thus, revealed that the disease causing missense mutations reduce the conformational
heterogeneity of the intrinsically disordered proteins and furthermore, they are
“locked” in one or two of those conformational states that presumably disfavour binding of the
IDRs with their cognate interacting partners.