Revealing the important role of allosteric property in sucrose phosphate synthase from sugarcane with N-terminal domain deletion

[摘要] Sucrose occupies many essential roles to control regulation of carbon partitioning in plants, including prokaryotic cells. Sucrose phosphate synthase (SPS; EC 2.4.1.14) is a key enzyme to catalyze the form of sucrose in primary sucrose synthesis pathway. Plants SPS has a molecular size around 120 kDa, which consists of N-terminal domain, C-terminal domain, and central domain. We produced the recombinant sugarcane SPS (SoSPS1) in Escherichia coli, however, the expression often appears to be a shorter form with retained enzyme activity. In our result, we reported that the shorter form is suggested to have a truncated N-terminal 20-kDa region. The truncated form of So SPS1 (ΔN-SPS) tends to enhance the specific activity 10-fold compared to full-length SoSPS1. The full-lenght SoSPS1 showed a remarkable allosteric activation by glucose-6-phosphate (G6P), while none of the N-terminal truncated form had such a characteristic. By kinetic analysis of full-length SoSPS1, a higher substrate affinity was shown in the presence of G6P. Conversely, the ΔN-SPS showed a similar substrate affinity whether G6P was added or not. Based on these results, we revealed that N-terminal region of SoSPS1 has essential role for allosteric regulation by G6P and may function like a suppressor domain for the enzyme activity.

[发布机构] Prodi Magister Bioteknologi, Universitas Jember, Jl. Kalimantan 37, Jember; 68121, Indonesia^1;Laboratorium Bioteknologi Dan Biologi Molekul, UPT Laboratorium Terpadu Dan Sentra Inovasi CDAST, Jl. Kalimantan 37, Jember; 68121, Indonesia^2

[效力级别] 化学 [学科分类] 生物科学（综合）

[关键词] Allosteric activation;Allosteric properties;Allosteric regulation;Carbon partitioning;Glucose 6 phosphates;N-terminal domains;Substrate affinity;Sucrose-phosphate synthase