ISSN:
1432-1017
Keywords:
Key wordsα-actinin
;
Spectrin-like repeats
;
Dimer formation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract Protein constructs consisting of repeats 1–4, repeats 1–3 and repeats 2–4 of the rod domain of chicken α-actinin were expressed as fusion proteins in Escherichia coli. Based on the evidence of circular dichroism spectra and cooperative thermal unfolding profiles both truncated rod fragments were judged to have assumed the native structural fold. The thermal stabilities were in both cases significantly lower than that of the intact rod (repeats 1–4). Analyses by sedimentation equilibrium and velocity provided further evidence to show that fragment 1–4 is entirely dimeric in the concentration range of these experiments, resembling therefore the rod domain isolated by proteolytic digestion of native α-actinin. Fragment 2–4, and probably also 1–3, show concentration-dependent association, with dissociation constants, estimated by sedimentation equilibrium, in the 1–10 µM range. Thus, in confirmation of earlier work, all four repeats are re-quired to generate a maximally stable anti-parallel dimer (Kd∼10 pM), suggesting the presence of binding sites in all of them to allow for aligned pairing.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002490050057
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