1lfb
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(New page: 200px<br /><applet load="1lfb" size="450" color="white" frame="true" align="right" spinBox="true" caption="1lfb, resolution 2.8Å" /> '''THE X-RAY STRUCTURE O...)
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THE X-RAY STRUCTURE OF AN ATYPICAL HOMEODOMAIN PRESENT IN THE RAT LIVER TRANSCRIPTION FACTOR LFB1(SLASH)HNF1 AND IMPLICATIONS FOR DNA BINDING
Overview
The transcription factor LFB1/HNF1 from rat liver nuclei is a 628 amino, acid protein that functions as a dimer binding to the inverted palindrome, GTTAATN-ATTAAC consensus site. We have crystallized a 99 residue protein, containing the homeodomain portion of LFB1, and solved its structure using, X-ray diffraction data to 2.8 A resolution. The topology and orientation, of the helices is essentially the same as that found in the engrailed, MAT, alpha 2 and Antennapedia homeodomains, even though the LFB1 homeodomain, contains 21 more residues. The 21 residue insertion is found in an, extension of helix 2 and consequent lengthening of the connecting loop, between helix 2 and helix 3. Comparison with the engrailed homeodomain-DNA, complex indicates that the mode of interaction with DNA is similar in both, proteins, with a number of conserved contacts in the major groove. The, extra 21 residues of the LFB1 homeodomain are not involved in DNA binding., Binding of the LFB1 dimer to a B-DNA palindromic consensus sequence, requires either a conformational change of the DNA (presumably bending), or a rearrangement of the subunits relative to the DNA.
About this Structure
1LFB is a Single protein structure of sequence from Rattus norvegicus. Full crystallographic information is available from OCA.
Reference
The X-ray structure of an atypical homeodomain present in the rat liver transcription factor LFB1/HNF1 and implications for DNA binding., Ceska TA, Lamers M, Monaci P, Nicosia A, Cortese R, Suck D, EMBO J. 1993 May;12(5):1805-10. PMID:8491173
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