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Alpha-lactalbumin possesses a distinct zinc binding site.

The Journal of biological chemistry (1993-09-15)
J Ren, D I Stuart, K R Acharya
ABSTRACT

It has been proposed that the binding of Zn2+ to alpha-lactalbumin switches the conformation to one akin to a state intermediate in the folding of the protein. However, the high resolution x-ray crystal structure of human alpha-lactalbumin-Zn2+ complex at 1.7-A resolution (pH 7.6) does not reveal any significant change in conformation from the native state. The Zn2+ ion binds specifically in the "cleft" of alpha-lactalbumin (the region which forms the active site of the homologous protein lysozyme). This may suggest a possible role for Zn2+ binding in lactose synthase complex. The coordination of the Zn2+ ion involves a symmetry-related molecule in the crystal, the crystal contacts being stabilized by a SO4(2-) ion bound at the interface between three molecules.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
α-Lactalbumin from bovine milk, Type III, calcium depleted, ≥85% (PAGE), lyophilized powder
Sigma-Aldrich
α-Lactalbumin from bovine milk, Marker for non-denaturing PAGE
Sigma-Aldrich
α-Lactalbumin from bovine milk, For use as a marker in SDS-PAGE
Sigma-Aldrich
α-Lactalbumin from bovine milk, Type I, ≥85% (PAGE), lyophilized powder
Sigma-Aldrich
α-Lactalbumin from human milk, ≥95% (SDS-PAGE), lyophilized powder
Sigma-Aldrich
Lactalbumin