Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1978 Oct;75(10):4848-52.
doi: 10.1073/pnas.75.10.4848.

Glucose-induced conformational change in yeast hexokinase

Glucose-induced conformational change in yeast hexokinase

W S Bennett Jr et al. Proc Natl Acad Sci U S A. 1978 Oct.

Abstract

The A isozyme of yeast hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1) crystallized as a complex with glucose has a conformation that is dramatically different from the conformation of the B isozyme crystallized in the absence of glucose. Comparison of the high-resolution structures shows that one lobe of the molecule is rotated by 12 degrees relative to the other lobe, resulting in movements of as much as 8 A in the polypeptide backbone and closing the cleft between the lobes into which glucose is bound. The conformational change is produced by the binding of glucose (R.C. McDonald, T.A. Steitz, and D.M. Engelman, unpublished data) and is essential for catalysis [Anderson, C.M., Stenkamp, R.E., McDonald, R.C. & Steitz, T.A. (1978) J. Mol. Biol. 123, 207-219] and thus provides an example of induced fit. The surface area of the hexokinase A-glucose complex exposed to solvent is smaller than that of native hexokinase B. By using the change in exposed surface area to estimate the hydrophobic contribution to the free energy changes upon glucose binding, we find that the hydrophobic effect alone favors the active conformation of hexokinase in the presence and absence of sugar. The observed stability of the inactive conformation of the enzyme in the absence of substrates may result from a deficiency of complementary interactions within the cavity that forms when the two lobes close together.

PubMed Disclaimer

References

    1. J Biol Chem. 1955 Jun;214(2):765-73 - PubMed
    1. J Mol Biol. 1978 Aug 5;123(2):207-19 - PubMed
    1. J Mol Biol. 1978 Jul 25;123(1):15-33 - PubMed
    1. J Mol Biol. 1978 Jul 25;123(1):1-13 - PubMed
    1. Annu Rev Biophys Bioeng. 1977;6:151-76 - PubMed

Publication types

LinkOut - more resources