PMID: 27187112

Authors:

Dixit K, Pande A, Pande J, Sarma SP

Title:

Nuclear Magnetic Resonance Structure of a Major Lens Protein, Human gammaC-Crystallin: Role of the Dipole Moment in Protein Solubility.

Journal:

Biochemistry. 2016 May 23.

Abstract:

A hallmark of the crystallin proteins is their exceptionally high solubility, which is vital for maintaining the high refractive index of the eye lens. Human gammaC-crystallin is a major gamma-crystallin whose mutant forms are associated with congenital cataracts but whose three-dimensional structure is not known. An earlier study of a homology model concluded that human gammaC-crystallin has low intrinsic solubility, mainly because of the atypical magnitude and fluctuations of its dipole moment. On the contrary, the high-resolution tertiary structure of human gammaC-crystallin determined here shows unequivocally that it is a highly soluble, monomeric molecule in solution. Notable differences between the orientations and interactions of several side chains are observed upon comparison to those in the model. No evidence of the pivotal role ascribed to the effect of dipole moment on protein solubility was found. The nuclear magnetic resonance structure should facilitate a comprehensive understanding of the deleterious effects of cataract-associated mutations in human gammaC-crystallin.