Section 46
Chapter 45,112

A short, disordered protein region mediates interactions between the homeodomain of the yeast alpha 2 protein and the MCM1 protein

Vershon, A.K.; Johnson, A.D.

Cell 72(1): 105-112


ISSN/ISBN: 0092-8674
PMID: 8422672
DOI: 10.1016/0092-8674(93)90054-t
Accession: 045111114

Homeodomains are folded into a characteristic three-dimensional structure capable of recognizing DNA in a sequence-specific manner. We show that correct target site selection by the yeast alpha 2 protein requires, as well as its homeodomain, an adjacent short and apparently unstructured region of the protein. This flexible homeodomain extension is responsible for specifying an interaction with a second regulatory protein, MCM1, which permits the cooperative binding of the two proteins to an operator. Two additional experiments suggest that this extension-homeodomain arrangement is likely to have some generality. First, when the extension of alpha 2 is grafted onto the Drosophila engrailed homeodomain, it yields a protein with the DNA binding specificity of engrailed and the ability to bind cooperatively to DNA with MCM1. Second, the alpha 2 extension specifies interaction not only with the yeast MCM1 protein, but also with the related human protein SRF.

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