U12-type catalytic step 1 spliceosome
A spliceosomal complex that is formed by the displacement of the U11 and U4atac snRNPs from the precatalytic spliceosome; the U12, U5 and U6atac snRNPs remain associated with the mRNA. This complex, sometimes called the activated spliceosome, is the catalytically active form of the spliceosome, and includes many proteins in addition to those found in the U12, and U5 and U6atac snRNPs.
GO:0005689
U12-type spliceosomal complex
is_a
GO:0071012
catalytic step 1 spliceosome
is_a
AT-AC catalytic step 1 spliceosome
narrow
U12-type activated spliceosome
exact
mammalian U12-type spliceosomal complex B*
narrow
mammalian U12-type spliceosomal complex B2
narrow
minor catalytic step 1 spliceosome
exact
yeast U12-type spliceosomal complex A1
narrow