1K98

AdoMet complex of MetH C-terminal fragment

Summary for 1K98

• Entry DOI: 10.2210/pdb1k98/pdb
• Related: 1bmd 1k7y 1msk
• Descriptor: Methionine synthase, SULFATE ION, COBALAMIN (3 entities in total)
• Functional Keywords: adomet binding, motion of 4-helix bundle, domain interactions, transferase
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 66285.56

Authors

Bandarian, V.,Pattridge, K.A.,Lennon, B.W.,Huddler, D.P.,Matthews, R.G.,Ludwig, M.L. (deposition date: 2001-10-27, release date: 2001-12-21, Last modification date: 2023-08-16)

Primary citation

Bandarian, V.,Pattridge, K.A.,Lennon, B.W.,Huddler, D.P.,Matthews, R.G.,Ludwig, M.L.
Domain alternation switches B(12)-dependent methionine synthase to the activation conformation.
Nat.Struct.Biol., 9:53-56, 2002

PubMed Abstract: B(12)-dependent methionine synthase (MetH) from Escherichia coli is a large modular protein that uses bound cobalamin as an intermediate methyl carrier. Major domain rearrangements have been postulated to explain how cobalamin reacts with three different substrates: homocysteine, methyltetrahydrofolate and S-adenosylmethionine (AdoMet). Here we describe the 3.0 A structure of a 65 kDa C-terminal fragment of MetH that spans the cobalamin- and AdoMet-binding domains, arranged in a conformation suitable for the methyl transfer from AdoMet to cobalamin that occurs during activation. In the conversion to the activation conformation, a helical domain that capped the cofactor moves 26 A and rotates by 63 degrees, allowing formation of a new interface between cobalamin and the AdoMet-binding (activation) domain. Interactions with the MetH activation domain drive the cobalamin away from its binding domain in a way that requires dissociation of the axial cobalt ligand and, thereby, provide a mechanism for control of the distribution of enzyme conformations.

PubMed: 11731805
DOI: 10.1038/nsb738

Experimental method

X-RAY DIFFRACTION (3.75 Å)