5WC9

Human Pit-1 and 4xCATT DNA complex

Summary for 5WC9

• Entry DOI: 10.2210/pdb5wc9/pdb
• Descriptor: Pituitary-specific positive transcription factor 1, DNA (5'-D(*CP*CP*AP*TP*TP*CP*AP*TP*TP*CP*AP*TP*TP*CP*AP*TP*TP*CP*GP*GP*A)-3'), DNA (5'-D(*CP*CP*GP*AP*AP*TP*GP*AP*AP*TP*GP*AP*AP*TP*GP*AP*AP*TP*GP*GP*T)-3') (3 entities in total)
• Functional Keywords: transcription regulation, dna-protein complex, dna binding protein
• Biological source: Homo sapiens (Human); More
• Cellular location: Nucleus : P28069
• Total number of polymer chains: 8
• Total formula weight: 96804.21

Authors

Agarwal, S.,Cho, T.Y. (deposition date: 2017-06-29, release date: 2017-11-22, Last modification date: 2023-10-04)

Primary citation

Agarwal, S.,Cho, T.Y.
Biochemical and structural characterization of a novel cooperative binding mode by Pit-1 with CATT repeats in the macrophage migration inhibitory factor promoter.
Nucleic Acids Res., 46:929-941, 2018

PubMed Abstract: Overexpression of the proinflammatory cytokine macrophage migration inhibitory factor (MIF) is linked to a number of autoimmune diseases and cancer. MIF production has been correlated to the number of CATT repeats in a microsatellite region upstream of the MIF gene. We have characterized the interaction of pituitary-specific positive transcription factor 1 (Pit-1) with a portion of the MIF promoter region flanking a microsatellite polymorphism (-794 CATT5-8). Using fluorescence anisotropy, we quantified tight complex formation between Pit-1 and an oligonucleotide consisting of eight consecutive CATT repeats (8xCATT) with an apparent Kd of 35 nM. Using competition experiments we found a 23 base pair oligonucleotide with 4xCATT repeats to be the minimum DNA sequence necessary for high affinity interaction with Pit-1. The stoichiometry of the Pit-1 DNA interaction was determined to be 2:1 and binding is cooperative in nature. We subsequently structurally characterized the complex and discovered a completely novel binding mode for Pit-1 in contrast to previously described Pit-1 complex structures. The affinity of Pit-1 for the CATT target sequence was found to be highly dependent on cooperativity. This work lays the groundwork for understanding transcriptional regulation of MIF and pursuing Pit-1 as a therapeutic target to treat MIF-mediated inflammatory disorders.

PubMed: 29186613
DOI: 10.1093/nar/gkx1183

Experimental method

X-RAY DIFFRACTION (3.15 Å)