spliceosome B complex (precatalytic spliceosome)

Function: - 3rd complex of spliceosome assembly - the U4/U5/U6 tri-snRNP is recruited to the assembling spliceosome 'complex A' to form 'complex B' & following several rearrangements, 'Complex C' (the splicesome) is activated for catalysis Structure: - consist of hnRNA, U1 snRNP, U2 snRNP, U4 snRNP, U5 snRNP, U6 snRNP, U2AF

References

- Wikipedia: Spliceosome http://en.wikipedia.org/wiki/spliceosome