Kim Jeong Seon, Chen Zhenhang, Espinosa Garcia Sara Andrea, Buhlheller Christoph, Zhang Botao, Richards Stephen J, Chen Tingfei, Wu Jingjing, Bruntz Ronald C, Gilliam Marisa E, Yamauchi Mitsuo, Liang Bo, Guo Houfu
Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA.
Markey Cancer Center, University of Kentucky, Lexington, KY, USA.
Nat Commun. 2025 Jul 21;16(1):6704. doi: 10.1038/s41467-025-61973-x.
Collagen glucosyltransferases catalyze collagen glucosylation critical for biology and diseases, yet their structural regulation remains unclear. Here, we report crystal structures of a mimiviral collagen glucosyltransferase in its apo form and in complexes with uridine diphosphate (UDP) and the disaccharide product. We reveal that the enzyme forms a homodimer, stabilized by a loop from one subunit locking into a cleft on the other, enabling UDP-glucose binding cooperativity and enzymatic activity, a property conserved in the human homolog. The structures support an induced fit model for UDP interaction. The dimerization also forms an extended cleft flanked by two active sites, likely facilitating collagen recognition. Unexpectedly, the mimiviral enzyme also synthesizes a prebiotic disaccharide kojibiose. An elongated pocket near the active site allows the enzyme to use UDP-glucose and glucose for kojibiose production. We confirm the enzyme's kojibiose synthesis activity in vitro and in vivo. These insights inform glucosyltransferase function and open new avenues for inhibitor development and kojibiose biosynthesis.
胶原蛋白葡萄糖基转移酶催化对生物学和疾病至关重要的胶原蛋白糖基化，但它们的结构调控仍不清楚。在这里，我们报告了一种拟病毒胶原蛋白葡萄糖基转移酶的晶体结构，包括其无配体形式以及与尿苷二磷酸（UDP）和二糖产物形成的复合物的结构。我们发现该酶形成同型二聚体，一个亚基的环锁定到另一个亚基的裂隙中从而使其稳定，这使得UDP-葡萄糖结合具有协同性并具备酶活性，这种特性在人类同源物中保守。这些结构支持UDP相互作用的诱导契合模型。二聚化还形成了一个由两个活性位点侧翼的延伸裂隙，可能有助于胶原蛋白识别。出乎意料的是，这种拟病毒酶还能合成益生元二糖曲二糖。活性位点附近的一个细长口袋使该酶能够利用UDP-葡萄糖和葡萄糖来生产曲二糖。我们在体外和体内证实了该酶的曲二糖合成活性。这些见解为葡萄糖基转移酶的功能提供了信息，并为抑制剂开发和曲二糖生物合成开辟了新途径。
