X-Ray structure of P. shermanii methylmalonyl-CoA mutase in complex with 2-carboxypropyl-CoA and
AdoCbl.
(a) The catalytically active α subunit in which the N-terminal
domain is cyan with the β strands of its α/β barrel
orange, and the C-terminal domain is pink. The 2-carboxypropyl-CoA (magenta)
and AdoCbl (green) are drawn in space-filling form. The
2-carboxypropyl-CoA passes through the center of the α/β barrel and is oriented such that the
methylmalonyl group of methylmalonyl-CoA would contact the corrin ring of the
AdoCbl, which is sandwiched between the enzyme's N- and C-terminal domains.
(b)
The arrangement of the AdoCbl and 2-carboxypropyl-CoA molecules which, together
with the side chain of His 610, are represented in stick form colored according
to atom type (AdoCbl and His C green, 2-carboxypropyl-CoA C cyan, N blue, O
red, P magenta, and S yellow). The corrin ring's Co atom is represented by a
lavender sphere and the α/β barrel's β strands
are represented by orange ribbons. The view is similar to that in Part a.
Note that the DMB group (bottom) has swung away from the corrin ring
(seen edgewise) to be replaced by the side chain of His 610 from the C-terminal
domain and that the 5'-deoxyadenosyl group is unseen (due to disorder). [Based
on an X-ray structure by Philip Evans, MRC Laboratory of Molecular Biology,
Cambridge, U.K. PDBid 7REQ.]