Prokaryotic Expression of the UGPASE Gene of Dendrobium Officinale and Its Functional Analysis

<title>Abstract</title> As is proven, the UGPase gene as a sugar metaboliser in <italic>Dendrobium officinale</italic> weigh heavily, yet little is known about the substance’s structural and functional roles. To solve this problem, the biological properties of UGPase were investigated in this paper, and the gene encoding UGPase (UDP - glucose pyrophosphorylase) from <italic>Dendrobium officinale</italic> was successfully transformed into <italic>Escherichia coli</italic> BL21 (DE3) to construct an overexpression recombinant strain. UGPase is a stable hydrophilic protein nucleotidyltransferase. The molecular formula is C ₂₃₅₁ H ₃₇₄₇ N ₆₀₃ O ₇₀₈ S ₈ , the theoretical molecular weight is 52.04 kD, the theoretical isoelectric point is 5.08 and the instability index is 27.95. Irregular convolutions as well as α-helices are the main secondary structures of UGPases, and they constitute the main backbone of UGPases. The fusion protein was obtained in vitro and confirmed by Western Blot. The enzymatic activity of the recombinant protein UGPase was determined using different substrates and the recombinant protein UGPase was enzymatically active. Compared with the control group, recombinant pET-32a-UGPase was more tolerant to low temperature at -20 ℃, high temperature at 50 ℃, in 1200 mmol/L sorbitol. This study aims to predict the protein structure, express the protein in a prokaryotic expression system and to detect the resistance of UGPase in <italic>Dendrobium officinale</italic> , which provides an insight into the biological properties of UGPase in <italic>Dendrobium officinale</italic> .