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Cloning, Expression and Characterization of Maltooligosyltrehalose Synthase from Nostoc Flagelliforme

Author: ShenRongRong
Tutor: WangQuanXi
School: Shanghai Normal University
Course: Hydrobiology
Keywords: Nostoc sp Maltooligosyl trehalose synthase Drought Cyanobacteria
CLC: Q943.2
Type: Master's thesis
Year: 2010
Downloads: 73
Quote: 1
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Abstract

Trehalose metabolic pathways and related metabolic enzymes in biological engineering research has been a focus of the study and hotspots . Both from the theoretical research and applications have shown a significant value and significance . Nostoc sp has a strong resistance, can withstand extreme adverse environmental stress . The laboratory in 2007 by drought stress Nostoc algae found in the presence of trehalose , this study further in vivo trehalose metabolism and its relationship between resistance to do some exploring . In this study, degenerate primers designed from Nostoc algae (Nostoc flagelliforme Born.Et Flah.) Cloned a genomic DNA fragment encoding may participate trehalose metabolism maltooligosyl trehalose synthase (NfMTS). NfMTS gene is 2799bp, encoding 933 amino acids , to form a 106.6KD size expressed protein . The gene encoding the amino acid sequence comprises four maltooligosyl trehalose synthase highly conserved regions . Expressed in E. coli NfMTS, the recombinant protein can be converted into maltose maltodextrin, trehalose , that this protein has a trehalose synthase maltooligosyl function. Obtained through the double reciprocal plot of the recombinant enzyme Michaelis constant for the 1.87 mM ( six malt sugar as substrate ) , the optimum temperature and pH of the enzyme reaction was 50 ℃ and 7.0 , respectively . Under drought stress , the Nostoc algae accumulation of trehalose and sucrose were significantly increased, maltose, trehalose synthase expression also showed an increasing trend . However , trehalose accumulation less than about 0.36 mg · g-1DW, and the accumulation of a large amount of sugar , which is about 0.90 mg · g-1DW, which indicates the trehalose and sucrose in Nostoc sp anti- drought stress have played a role, but may be sucrose instead of trehalose in Nostoc sp experiencing drought stress as a chemical chaperone played a role . This study investigated the molecular level seaweed trehalose key enzyme in the metabolic pathway , the results obtained for the study of seaweed trehalose metabolic pathway provides a foundation, but also conducive to our in-depth understanding of trehalose metabolism and seaweed function .

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