Structures of MfnG, an O-methyltranseferase involved in the biosynthese of marformycins, from multiple crystal forms

Conference: 2022: 72nd ACA Annual Meeting
Mitchell D. Miller Poster Author
Rice University
Houston, TX 
 
Kuan-Lin Wu Additional Author
Rice University
Houston, TX 
 
Weijun Xu Additional Author
Rice University
Houston, TX 
 
Han Xiao Additional Author
Rice University
Houston, TX 
 
George N. Phillips, Jr. Additional Author
Rice University
Houston, TX 
 
07/31/2022: 5:30 PM - 7:30 PM
Poster Session 
Portland Marriott Downtown Waterfront 
Room: Exhibit Hall 

Description

Marformycins are anti-infective natural products isolated from a deep sea sediment-derived Streptomyces drozdowiczii strain. These cyclodepsipetides contain O-methyl-D-Tyr. Liu et al., (Org. Lett. 2015, 17, 1509–1512) identified a SAM-dependent O-methyltransferase, MfnG, in the marformycins biosynthetic gene cluster and found it capable of methylating the phenoic oxygen of both D-Tyr and L-Tyr in vitro.

To better understand this enzyme's structural recognition and function, we have determined the MfnG structure using X-ray crystallography. Despite adding S-adenosyl-L-methionine (SAM/AdoMet) to the protein during crystallization, we found the spent product, S-Adenosyl-L-homocysteine (SAH/AdoHcy), bound. Since the SAH is unreactive, we were able to soak in L-Tyrosine to obtain a structure with the methyl doner product (SAH) and a methyl acceptor substrate (L-Tyr).

We found MfnG could crystalize from a number of different screening conditions and that these crystals had different unit cell parameters. To date, we have phased 5 forms (2 forms in P212121, 2 forms in P21 and a P1 form), which contain one to four dimers (2-8 protomers) per asymmetric unit. Here we compare the packing arrangement in these different crystal packing forms.


This work was supported in part by the NSF (STC 1231306), NIH/NIGMS (R01-GM115261, R35-GM133706), NIH/NIAID (R01-AI165079), NIH/NCI (R01-CA217255, R21-CA255894), US DOD (W81XWH-21-1-0789), Texas CPRIT (RR170014) and the Robert A. Welch Foundation (C-1970). The content is solely the responsibility of the authors and does not necessarily represent the official views of the Funders.