Compositional and Conformational Analysis of Sperm Nucleus Basic Proteins from the Bivalve Mollusk Crassostrea virginica

Arreguín Espinosa, Roberto; Chavelas Adame, A. Eneas; García Hernández, Enrique; Salazar Campos, M. Zayil

Compositional and Conformational Analysis of Sperm Nucleus Basic Proteins from the Bivalve Mollusk Crassostrea virginica

2002

Arreguín Espinosa, Roberto | Chavelas Adame, A. Eneas | García Hernández, Enrique | Salazar Campos, M. Zayil

We report a study on the basic proteins from sperm nucleus of the bivalve mollusk Crassostrea virginica. This is the first study in its type reported for this specie of wide distribution and high commercial interest. The electrophoretic behavior of total basic proteins was obtained, revealing the characteristic composition of O-group. Using perchloric acid extraction followed by reverse-phase high performance liquid chromatography, a germinal histone H1-2 protein was isolated. An analysis of the circular dichroism spectrum of this protein revealed the lack of regular elements of secondary structure. The H1-2 protein was subjected to a progressive thermal perturbation, observing no abrupt CD-signal change in the scanned temperature range; in contrast, a continuous and significant diminution of optical activity was observed. Overall, these observations indicate that at room temperature the germinal histone is a non-compact intermediate that preserves some secondary structure, and which transits to a more unfolded state upon temperature increase.

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