Study of α-Crystallin Structure by Small Angle Neutron Scattering with Contrast Variation

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A. V. Krivandin^1*, T. N. Murugova², A. I. Kuklin², K. O. Muranov¹, N. B. Poliansky¹, V. L. Aksenov², and M. A. Ostrovsky¹

¹Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, ul. Kosygina 4, 119334 Moscow, Russia; fax: (499) 137-4101; E-mail: a.krivandin@sky.chph.ras.ru

²Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, ul. Joliot Curie 6, 141980 Dubna, Moscow Region, Russia; fax: (496) 216-5484; E-mail: kuklin@nf.jinr.ru

^* To whom correspondence should be addressed.

Received May 27, 2010

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The structure of the oligomeric protein α-crystallin from bovine eye lens was investigated by small-angle neutron scattering (SANS) with contrast variation. Based on the SANS curves, the match point for α-crystallin (43% D₂O) and its average scattering length density at this point (2.4·10¹⁰ cm^–2) were evaluated. The radius of gyration and the distance distribution functions for α-crystallin were calculated. On the basis of these calculations, it was concluded that α-crystallin is characterized by homogeneous distribution of scattering density in the domains inaccessible for water penetration, and all polypeptide subunits in α-crystallin oligomers undergo equal deuteration. The latter indicates that all α-crystallin subunits are equally accessible for water and presumably for some other low molecular weight substances. These conclusions on the α-crystallin structure (homogeneous distribution of scattering density and equal accessibility of all subunits for low molecular weight substances) should be taken into account when elaborating α-crystallin quaternary structure models.

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KEY WORDS: α-crystallin, quaternary structure, small-angle neutron scattering, contrast variation

DOI: 10.1134/S0006297910110039

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