2BN6: P-Element Somatic Inhibitor Protein

P-element transposition in Drosophila is regulated by tissue-specific alternative splicing of the P-element transposase pre-mRNA. In somatic cells, the P-element somatic inhibitor (PSI) protein binds to exon 3 of the pre-mRNA and recruits U1 small nuclear ribonucleoprotein (snRNP) to the F1 pseudo-splice site. This abrogates binding of U1 snRNP to the genuine 5' splice site, thereby preventing excision of the third intron. Two homologous short sequences, referred to as the A and B boxes, near the C terminus of PSI bind to U1-70k protein within U1 snRNP. We have now mapped the AB box-binding site of U1-70k to a short proline-rich sequence at the C terminus. Our NMR study shows that the B box forms an anti-parallel helical hairpin in which four highly conserved aromatic residues form a cluster on one face of the first helix. This hydrophobic cluster interacts extensively with the proline-rich region of the U1-70k protein.
PDB ID: 2BN6Download
MMDB ID: 34460
PDB Deposition Date: 2005/3/21
Updated in MMDB: 2007/11
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Biological Unit for 2BN6: monomeric; determined by author
Molecular Components in 2BN6
Label Count Molecule
Protein (1 molecule)
Molecule annotation
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Citing MMDB