<sod>This protein belongs to the HNF1 [[homeobox]] family.<ref name=":2" /> It contains 3 functional domains: an [[N-terminus|N-terminal]] [[dimerization]] domain ([[Amino acid|residues]] 1–32), a bipartite DNA-binding motif containing an atypical POU-[[homeodomain]] (residues 98–280), and a [[C-terminus|C-terminal]] transactivation domain (residues 281–631).<ref name=":3">{{Cite journal|last=Chi|first=Young-In|last2=Frantz|first2=J. Daniel|last3=Oh|first3=Byung-Chul|last4=Hansen|first4=Lone|last5=Dhe-Paganon|first5=Sirano|last6=Shoelson|first6=Steven E.|date=2002-11-01|title=Diabetes mutations delineate an atypical POU domain in HNF-1alpha|url=https://www.ncbi.nlm.nih.gov/pubmed/12453420|journal=Molecular Cell|volume=10|issue=5|pages=1129–1137|issn=1097-2765|pmid=12453420}}</ref><ref name=":4">{{Cite journal|last=Narayana|first=Narendra|last2=Phillips|first2=Nelson B.|last3=Hua|first3=Qing-xin|last4=Jia|first4=Wenhua|last5=Weiss|first5=Michael A.|date=2006-09-22|title=Diabetes mellitus due to misfolding of a beta-cell transcription factor: stereospecific frustration of a Schellman motif in HNF-1alpha|url=https://www.ncbi.nlm.nih.gov/pubmed/16930618|journal=Journal of Molecular Biology|volume=362|issue=3|pages=414–429|doi=10.1016/j.jmb.2006.06.086|issn=0022-2836|pmid=16930618}}</ref> There is also a flexible linker (residues 33–97) which connects the dimerization and DNA binding domains.<ref>{{Cite journal|last=Narayana|first=Narendra|last2=Phillips|first2=Nelson B.|last3=Hua|first3=Qing-xin|last4=Jia|first4=Wenhua|last5=Weiss|first5=Michael A.|date=2006-09-22|title=Diabetes mellitus due to misfolding of a beta-cell transcription factor: stereospecific frustration of a Schellman motif in HNF-1alpha|url=https://www.ncbi.nlm.nih.gov/pubmed/16930618|journal=Journal of Molecular Biology|volume=362|issue=3|pages=414–429|doi=10.1016/j.jmb.2006.06.086|issn=0022-2836|pmid=16930618}}</ref> Crystal structures have been solved for the dimerization domain, which forms a four-helix bundle where two [[α helices]] are separated by a turn; the DNA-binding motif, which forms a [[helix-turn-helix]] structure; and the POU-homeodomain, which is composed of three α helices, contained in the motif. This homeodomain is considered atypical due to an extended loop inserted between the second and third helices relative to the canonical homeodomain fold. The atypical insertion is thought to stabilize the interface to improve [[Transcription (genetics)|transcriptional]] efficiency.<ref name=":3" /> Meanwhile, the dimerization domain is responsible for the homo- and heterodimerization of HNF-1α. The resulting dimer contains a rigid “mini-zipper”, comprising α-helices 1 and 1′, linked by a non-canonical tight turn to a flexible C-terminal comprising α-helices 2 and 2′.<ref name=":4" /><eod>
<sod>This protein belongs to the HNF1 [[homeobox]] family.<ref name=":2" /> It contains 3 functional domains: an [[N-terminus|N-terminal]] [[dimerization]] domain ([[Amino acid|residues]] 1–32), a bipartite DNA-binding motif containing an atypical POU-[[homeodomain]] (residues 98–280), and a [[C-terminus|C-terminal]] transactivation domain (residues 281–631).<ref name=":3">{{cite journal | vauthors = Chi YI, Frantz JD, Oh BC, Hansen L, Dhe-Paganon S, Shoelson SE | title = Diabetes mutations delineate an atypical POU domain in HNF-1alpha | journal = Molecular Cell | volume = 10 | issue = 5 | pages = 1129–37 | date = November 2002 | pmid = 12453420 }}</ref><ref name=":4">{{cite journal | vauthors = Narayana N, Phillips NB, Hua QX, Jia W, Weiss MA | title = Diabetes mellitus due to misfolding of a beta-cell transcription factor: stereospecific frustration of a Schellman motif in HNF-1alpha | journal = Journal of Molecular Biology | volume = 362 | issue = 3 | pages = 414–29 | date = September 2006 | pmid = 16930618 | doi = 10.1016/j.jmb.2006.06.086 }}</ref> There is also a flexible linker (residues 33–97) which connects the dimerization and DNA binding domains.<ref>{{cite journal | vauthors = Narayana N, Phillips NB, Hua QX, Jia W, Weiss MA | title = Diabetes mellitus due to misfolding of a beta-cell transcription factor: stereospecific frustration of a Schellman motif in HNF-1alpha | journal = Journal of Molecular Biology | volume = 362 | issue = 3 | pages = 414–29 | date = September 2006 | pmid = 16930618 | doi = 10.1016/j.jmb.2006.06.086 }}</ref> Crystal structures have been solved for the dimerization domain, which forms a four-helix bundle where two [[α helices]] are separated by a turn; the DNA-binding motif, which forms a [[helix-turn-helix]] structure; and the POU-homeodomain, which is composed of three α helices, contained in the motif. This homeodomain is considered atypical due to an extended loop inserted between the second and third helices relative to the canonical homeodomain fold. The atypical insertion is thought to stabilize the interface to improve [[Transcription (genetics)|transcriptional]] efficiency.<ref name=":3" /> Meanwhile, the dimerization domain is responsible for the homo- and heterodimerization of HNF-1α. The resulting dimer contains a rigid “mini-zipper”, comprising α-helices 1 and 1′, linked by a non-canonical tight turn to a flexible C-terminal comprising α-helices 2 and 2′.<ref name=":4" /><eod>