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Comparative Study
. 1978 Jan;75(1):113-6.
doi: 10.1073/pnas.75.1.113.

On the evolution of beta-galactosidase

J M Hood, A V Fowler, I Zabin
Comparative Study

On the evolution of beta-galactosidase

J M Hood et al. Proc Natl Acad Sci U S A. 1978 Jan.

Abstract

The amino acid sequence of beta-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1.23) has been compared to itself and to other proteins. Two segments, each of about 380 amino acids, comprising the first three-fourths of the polypeptide chain, were found to be very similar to each other. It is concluded that they are homologous. The carboxyl-terminal fourth has a high percentage of amino acid identities with dihydrofolate reductase of Escherichia coli, suggesting these sequences also are homologous. A model for the origin of beta-galactosidase is presented. The overall similarity of beta-galactosidase to lac repressor does not appear to be significant.

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References

    1. Proc Natl Acad Sci U S A. 1945 Jun;31(6):153-7 - PubMed
    1. J Mol Evol. 1977 Apr 29;9(2):121-30 - PubMed
    1. Annu Rev Biochem. 1977;46:573-639 - PubMed
    1. Proc Natl Acad Sci U S A. 1977 Apr;74(4):1507-10 - PubMed
    1. Eur J Biochem. 1977 Feb;72(3):613-24 - PubMed

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