Details

Autor(en) / Beteiligte

• Singh, Shanteri
• McCoy, Jason G.
• Zhang, Changsheng
• Bingman, Craig A.
• Phillips, George N.
• Thorson, Jon S.

Titel

Structure and Mechanism of the Rebeccamycin Sugar 4′-O-Methyltransferase RebM

Ist Teil von

• The Journal of biological chemistry, 2008-08, Vol.283 (33), p.22628-22636

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2008

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• The 2.65-Å crystal structure of the rebeccamycin 4′-O-methyltransferase RebM in complex with S-adenosyl-l-homocysteine revealed RebM to adopt a typical S-adenosylmethionine-binding fold of small molecule O-methyltransferases (O-MTases) and display a weak dimerization domain unique to MTases. Using this structure as a basis, the RebM substrate binding model implicated a predominance of nonspecific hydrophobic interactions consistent with the reported ability of RebM to methylate a wide range of indolocarbazole surrogates. This model also illuminated the three putative RebM catalytic residues (His140/141 and Asp166) subsequently found to be highly conserved among sequence-related natural product O-MTases from GC-rich bacteria. Interrogation of these residues via site-directed mutagenesis in RebM demonstrated His140 and Asp166 to be most important for catalysis. This study reveals RebM to be a member of the general acid/base-dependent O-MTases and, as the first crystal structure for a sugar O-MTase, may also present a template toward the future engineering of natural product MTases for combinatorial applications.