Crystal structure of a S-adenosyl-L-methionine-dependent O-methyltransferase-like enzyme from Aspergillus flavus

© 2020 Wiley Periodicals LLC..

S-adenosyl-L-methionine (SAM)-dependent methyltransferases (MTases) are widely distributed among almost all organisms and often characterized with conserved Rossmann fold, TIM barrel, and D×G×G×G motif. However, some MTases show no methyltransferase activity. In the present study, the crystal structure of LepI, one MTase-like enzyme isolated from A. flavus that catalyzes pericyclic reactions, was investigated to determine its structure-function relationship. The overall structure of LepI in complex with the SAM mimic S-adenosyl-L-homocysteine (SAH) (PDB ID: 6IV7) indicated that LepI is a tetramer in solution. The residues His133, Arg197, Arg295, and Asp296 located near the active site can form hydrogen bonds with the substrate, thus participating in catalytic reactions. The binding of SAH in LepI is almost identical to that in other resolved MTases; however, the location of catalytic residues differs significantly. Phylogenetic trials suggest that LepI proteins share a common ancestor in plants and algae, which may explain the conserved SAM-binding site. However, the accelerated evolution of A. flavus has introduced both functional and structural changes in LepI. More importantly, the residue Arg295, which is unique to LepI, might be a key determinant for the altered enzymatic behavior. Collectively, the differences in the composition of catalytic residues, as well as the unique tetrameric form of LepI, define its unique enzymatic behavior. The present work provides an additional understanding of the structure-function relationship of MTases and MTase-like enzymes.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:89

Enthalten in:

Proteins - 89(2021), 2 vom: 15. Feb., Seite 185-192

Sprache:

Englisch

Beteiligte Personen:

Liao, Lijing [VerfasserIn]
Zhou, Yuanze [VerfasserIn]
Peng, Ting [VerfasserIn]
Guo, Yan [VerfasserIn]
Zhao, Yucheng [VerfasserIn]
Zeng, Zhixiong [VerfasserIn]

Links:

Volltext

Themen:

7LP2MPO46S
979-92-0
Crystal structure
EC 2.1.1.-
EC 2.1.1.12
Evolution
Fungal Proteins
Journal Article
Methionine S-methyltransferase
Methyltransferases
Pericyclic reaction
Recombinant Proteins
Research Support, Non-U.S. Gov't
S-Adenosylhomocysteine
S-Adenosylmethionine
SAM-dependent methyltransferase

Anmerkungen:

Date Completed 24.05.2021

Date Revised 24.05.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1002/prot.26004

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM314485848