1an4
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STRUCTURE AND FUNCTION OF THE B/HLH/Z DOMAIN OF USF
OverviewOverview
The basic/helix-loop-helix/leucine zipper (b/HLH/Z) transcription factor, upstream stimulatory factor (USF) and its isolated DNA binding domain, undergo a random coil to alpha-helix folding transition on recognizing, their cognate DNA. The USF b/HLH cocrystal structure resembles the, structure of the b/HLH/Z domain of the homologous protein Max and reveals, (i) that the truncated, b/HLH DNA binding domain homodimerizes, forming a, parallel, left-handed four-helix bundle, and (ii) that the basic region, becomes alpha-helical on binding to the major groove of the DNA sequence, CACGTG. Hydrodynamic measurements show that the b/HLH/Z DNA binding domain, of USF exists as a bivalent homotetramer. This tetramer forms at the USF, physiological intranuclear concentration, and depends on the integrity of, the leucine zipper motif. The ability to bind simultaneously to two, independent sites suggests a role in DNA looping for the b/HLH/Z and, Myc-related families of eukaryotic transcription factors.
DiseaseDisease
Known diseases associated with this structure: Hyperlipidemia, familial combined, susceptibility to OMIM:[191523]
About this StructureAbout this Structure
1AN4 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Structure and function of the b/HLH/Z domain of USF., Ferre-D'Amare AR, Pognonec P, Roeder RG, Burley SK, EMBO J. 1994 Jan 1;13(1):180-9. PMID:8306960
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