Active site architecture of an acetyl xylan esterase indicates a novel cold adaptation strategy was written by Zhang, Yi;Ding, Hai-Tao;Jiang, Wen-Xin;Zhang, Xia;Cao, Hai-Yan;Wang, Jing-Ping;Li, Chun-Yang;Huang, Feng;Zhang, Xi-Ying;Chen, Xiu-Lan;Zhang, Yu-Zhong;Li, Ping-Yi. And the article was included in Journal of Biological Chemistry in 2021.Reference of 604-69-3 The following contents are mentioned in the article:
SGNH-type acetyl xylan esterases (AcXEs) play important roles in marine and terrestrial xylan degradation, which are necessary for removing acetyl side groups from xylan. However, only a few cold-adapted AcXEs have been reported, and the underlying mechanisms for their cold adaptation are still unknown because of the lack of structural information. Here, a cold-adapted AcXE, AlAXEase, from the Arctic marine bacterium Arcticibacterium luteifluviistationis SM1504T was characterized. AlAXEase could deacetylate xylooligosaccharides and xylan, which, together with its homologs, indicates a novel SGNH-type carbohydrate esterase family. AlAXEase showed the highest activity at 30 掳C and retained over 70% activity at 0 掳C but had unusual thermostability with a Tm value of 56 掳C. To explain the cold adaptation mechanism of AlAXEase, we next solved its crystal structure. AlAXEase has similar noncovalent stabilizing interactions to its mesophilic counterpart at the monomer level and forms stable tetramers in solutions, which may explain its high thermostability. However, a long loop containing the catalytic residues Asp200 and His203 in AlAXEase was found to be flexible because of the reduced stabilizing hydrophobic interactions and increased destabilizing asparagine and lysine residues, leading to a highly flexible active site. Structural and enzyme kinetic analyses combined with mol. dynamics simulations at different temperatures revealed that the flexible catalytic loop contributes to the cold adaptation of AlAXEase by modulating the distance between the catalytic His203 in this loop and the nucleophilic Ser32. This study reveals a new cold adaptation strategy adopted by the thermostable AlAXEase, shedding light on the cold adaptation mechanisms of AcXEs. This study involved multiple reactions and reactants, such as (2S,3R,4S,5R,6R)-6-(Acetoxymethyl)tetrahydro-2H-pyran-2,3,4,5-tetrayl tetraacetate (cas: 604-69-3Reference of 604-69-3).
(2S,3R,4S,5R,6R)-6-(Acetoxymethyl)tetrahydro-2H-pyran-2,3,4,5-tetrayl tetraacetate (cas: 604-69-3) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries. Because of their lack of hydrogen-bond-donating ability, esters do not self-associate. Consequently, esters are more volatile than carboxylic acids of similar molecular weight.Reference of 604-69-3
Referemce:
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