1IM8

Crystal structure of YecO from Haemophilus influenzae (HI0319), a methyltransferase with a bound S-adenosylhomocysteine

Summary for 1IM8

• Entry DOI: 10.2210/pdb1im8/pdb
• Descriptor: YecO, CHLORIDE ION, S-ADENOSYL-L-HOMOSELENOCYSTEINE, ... (4 entities in total)
• Functional Keywords: methyltransferase, adenosylhomocysteine, structural genomics, hypothetical protein, structure 2 function project, s2f, transferase
• Biological source: Haemophilus influenzae Rd
• Total number of polymer chains: 2
• Total formula weight: 56963.66

Authors

Lim, K.,Zhang, H.,Tempczyk, A.,Bonander, N.,Toedt, J.,Howard, A.,Eisenstein, E.,Herzberg, O.,Structure 2 Function Project (S2F) (deposition date: 2001-05-10, release date: 2001-11-07, Last modification date: 2024-11-20)

Primary citation

Lim, K.,Zhang, H.,Tempczyk, A.,Bonander, N.,Toedt, J.,Howard, A.,Eisenstein, E.,Herzberg, O.
Crystal structure of YecO from Haemophilus influenzae (HI0319) reveals a methyltransferase fold and a bound S-adenosylhomocysteine.
Proteins, 45:397-407, 2001

PubMed Abstract: The crystal structure of YecO from Haemophilus influenzae (HI0319), a protein annotated in the sequence databases as hypothetical, and that has not been assigned a function, has been determined at 2.2-A resolution. The structure reveals a fold typical of S-adenosyl-L-methionine-dependent (AdoMet) methyltransferase enzymes. Moreover, a processed cofactor, S-adenosyl-L-homocysteine (AdoHcy), is bound to the enzyme, further confirming the biochemical function of HI0319 and its sequence family members. An active site arginine, shielded from bulk solvent, interacts with an anion, possibly a chloride ion, which in turn interacts with the sulfur atom of AdoHcy. The AdoHcy and nearby protein residues delineate a small solvent-excluded substrate binding cavity of 162 A(3) in volume. The environment surrounding the cavity indicates that the substrate molecule contains a hydrophobic moiety and an anionic group. Many of the residues that define the cavity are invariant in the HI0319 sequence family but are not conserved in other methyltransferases. Therefore, the substrate specificity of YecO enzymes is unique and differs from the substrate specificity of all other methyltransferases sequenced to date. Examination of the Enzyme Commission list of methyltransferases prompted a manual inspection of 10 possible substrates using computer graphics and suggested that the ortho-substituted benzoic acids fit best in the active site.

PubMed: 11746687
DOI: 10.1002/prot.10004

Experimental method

X-RAY DIFFRACTION (2.2 Å)