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Crystal structure of the Epithiospecifier Protein, ESP from Arabidopsis thaliana
Structural highlights
FunctionESP_ARATH Converts glucosinolates both to epithionitriles and to simple nitriles in the presence of myrosinase. Promotes the formation of epithionitriles after hydrolysis of alkenylglucosinolates containing a terminal double bond. Mediates indol-3-acetonitrile (IACN) production from indol-3-ylmethyl glucosinolate. Acts as a negative regulator of senescence.[1] [2] [3] [4] [5] Publication Abstract from PubMedSpecifier proteins are important components of the glucosinolate-myrosinase system, which mediate plant defense against herbivory and pathogen attacks. Upon tissue disruption, glucosinolates are hydrolyzed to instable aglucones by myrosinases, and then aglucones will rearrange to form defensive isothiocyanates. Specifier proteins can redirect this reaction to form other products, such as simple nitriles, epithionitriles and organic thiocyanates instead of isothiocyanates based on the side chain structure of glucosinolate and the type of the specifier proteins. Nevertheless, the molecular mechanism underlying the different product spectrums of various specifier proteins was not fully understood. Here in this study, we solved the crystal structure of the Epithiospecifier Protein, ESP from Arabidopsis thaliana (AtESP) at 2.3 A resolution. Structural comparisons with the previously solved structure of thiocyanate forming protein, TFP from Thlaspi arvense (TaTFP) reveal that AtESP shows a dimerization pattern different from TaTFP. Moreover, AtESP harbors a slightly larger active site pocket than TaTFP and several residues around the active site are different between the two proteins, which might account for the different product spectrums of the two proteins. Together, our structural study provides important insights into the molecular mechanisms of specifier proteins and shed light on the basis of their different product spectrums. Crystal structure of the Epithiospecifier Protein, ESP from Arabidopsis thaliana provides insights into its product specificity.,Zhang W, Wang W, Liu Z, Xie Y, Wang H, Mu Y, Huang Y, Feng Y Biochem Biophys Res Commun. 2016 Sep 16;478(2):746-51. doi:, 10.1016/j.bbrc.2016.08.019. Epub 2016 Aug 4. PMID:27498030[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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