6BK3

Crystal structure of Os79 from O. sativa in complex with UDP and deoxynivalenol-3-glucoside (glucose moitey not resolved)

Summary for 6BK3

• Entry DOI: 10.2210/pdb6bk3/pdb
• Descriptor: UDP-glycosyltransferase 79, URIDINE-5'-DIPHOSPHATE, (3alpha,7alpha)-3,7,15-trihydroxy-12,13-epoxytrichothec-9-en-8-one, ... (4 entities in total)
• Functional Keywords: udp-glucosyltransferase, trichothecene, transferase
• Biological source: Oryza sativa Japonica Group (Rice)
• Total number of polymer chains: 1
• Total formula weight: 51844.68

Authors

Wetterhorn, K.,Gabardi, K.,Rayment, I. (deposition date: 2017-11-07, release date: 2017-11-29, Last modification date: 2023-10-04)

Primary citation

Wetterhorn, K.M.,Gabardi, K.,Michlmayr, H.,Malachova, A.,Busman, M.,McCormick, S.P.,Berthiller, F.,Adam, G.,Rayment, I.
Determinants and Expansion of Specificity in a Trichothecene UDP-Glucosyltransferase from Oryza sativa.
Biochemistry, 56:6585-6596, 2017

PubMed Abstract: Family 1 UDP-glycosyltransferases (UGTs) in plants primarily form glucose conjugates of small molecules and, besides other functions, play a role in detoxification of xenobiotics. Indeed, overexpression of a barley UGT in wheat has been shown to control Fusarium head blight, which is a plant disease of global significance that leads to reduced crop yields and contamination with trichothecene mycotoxins such as deoxynivalenol (DON), T-2 toxin, and many other structural variants. The UGT Os79 from rice has emerged as a promising candidate for inactivation of mycotoxins because of its ability to glycosylate DON, nivalenol, and hydrolyzed T-2 toxin (HT-2). However, Os79 is unable to modify T-2 toxin (T-2), produced by pathogens such as Fusarium sporotrichioides and Fusarium langsethii. Activity toward T-2 is desirable because it would allow a single UGT to inactivate co-occurring mycotoxins. Here, the structure of Os79 in complex with the products UDP and deoxynivalenol 3-O-glucoside is reported together with a kinetic analysis of a broad range of trichothecene mycotoxins. Residues associated with the trichothecene binding pocket were examined by site-directed mutagenesis that revealed that trichothecenes substituted at the C4 position, which are not glycosylated by wild-type Os79, can be accommodated in the binding pocket by increasing its volume. The H122A/L123A/Q202L triple mutation, which increases the volume of the active site and attenuates polar contacts, led to strong and equivalent activity toward trichothecenes with C4 acetyl groups. This mutant enzyme provides the broad specificity required to control multiple toxins produced by different Fusarium species and chemotypes.

PubMed: 29140092
DOI: 10.1021/acs.biochem.7b01007

Experimental method

X-RAY DIFFRACTION (2.17 Å)