1EG2

CRYSTAL STRUCTURE OF RHODOBACTER SPHEROIDES (N6 ADENOSINE) METHYLTRANSFERASE (M.RSRI)

Summary for 1EG2

• Entry DOI: 10.2210/pdb1eg2/pdb
• Descriptor: MODIFICATION METHYLASE RSRI, 5'-DEOXY-5'-METHYLTHIOADENOSINE (3 entities in total)
• Functional Keywords: rossmann fold, exocyclic amino dna methyltransferase rsri, dna binding, dna modification, dna methylation, structural genomics, psi, protein structure initiative, midwest center for structural genomics, mcsg, transferase
• Biological source: Rhodobacter sphaeroides
• Total number of polymer chains: 1
• Total formula weight: 35999.53

Authors

Scavetta, R.D.,Thomas, C.B.,Walsh, M.A.,Szegedi, S.,Joachimiak, A.,Gumport, R.I.,Churchill, M.E.A.,Midwest Center for Structural Genomics (MCSG) (deposition date: 2000-02-11, release date: 2000-10-18, Last modification date: 2024-02-07)

Primary citation

Scavetta, R.D.,Thomas, C.B.,Walsh, M.A.,Szegedi, S.,Joachimiak, A.,Gumport, R.I.,Churchill, M.E.
Structure of RsrI methyltransferase, a member of the N6-adenine beta class of DNA methyltransferases.
Nucleic Acids Res., 28:3950-3961, 2000

PubMed Abstract: DNA methylation is important in cellular, developmental and disease processes, as well as in bacterial restriction-modification systems. Methylation of DNA at the amino groups of cytosine and adenine is a common mode of protection against restriction endonucleases afforded by the bacterial methyltransferases. The first structure of an N:6-adenine methyltransferase belonging to the beta class of bacterial methyltransferases is described here. The structure of M. RSR:I from Rhodobacter sphaeroides, which methylates the second adenine of the GAATTC sequence, was determined to 1.75 A resolution using X-ray crystallography. Like other methyltransferases, the enzyme contains the methylase fold and has well-defined substrate binding pockets. The catalytic core most closely resembles the PVU:II methyltransferase, a cytosine amino methyltransferase of the same beta group. The larger nucleotide binding pocket observed in M. RSR:I is expected because it methylates adenine. However, the most striking difference between the RSR:I methyltransferase and the other bacterial enzymes is the structure of the putative DNA target recognition domain, which is formed in part by two helices on an extended arm of the protein on the face of the enzyme opposite the active site. This observation suggests that a dramatic conformational change or oligomerization may take place during DNA binding and methylation.

PubMed: 11024175
DOI: 10.1093/nar/28.20.3950

Experimental method

X-RAY DIFFRACTION (1.75 Å)