5NM9

Crystal structure of the placozoa Trichoplax adhaerens Smad4-MH1 bound to the GGCGC site.


ChainDomainClassArchitectureTopologyHomology
A3.90.520.10 Alpha Beta Alpha-Beta Complex Smad3 Chain A
B3.90.520.10 Alpha Beta Alpha-Beta Complex Smad3 Chain A

Protein Family Annotation Pfam Database Homepage

ChainsAccessionIdentifierDescriptionCommentsSource
A, BPF03165MH1 domain (MH1)MH1 domainThe MH1 (MAD homology 1) domain is found at the amino terminus of MAD related proteins such as Smads. This domain is separated from the MH2 domain by a non-conserved linker region. The crystal structure of the MH1 domain shows that a highly conserved ...The MH1 (MAD homology 1) domain is found at the amino terminus of MAD related proteins such as Smads. This domain is separated from the MH2 domain by a non-conserved linker region. The crystal structure of the MH1 domain shows that a highly conserved 11 residue beta hairpin is used to bind the DNA consensus sequence GNCN in the major groove, shown to be vital for the transcriptional activation of target genes. Not all examples of MH1 can bind to DNA however. Smad2 cannot bind DNA and has a large insertion within the hairpin that presumably abolishes DNA binding. A basic helix (H2) in MH1 with the nuclear localisation signal KKLKK has been shown to be essential for Smad3 nuclear import. Smads also use the MH1 domain to interact with transcription factors such as Jun, TFE3, Sp1, and Runx [1,3].
Domain
A, BPF03166MH2 domain (MH2)MH2 domain- Family