Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
Infection & Immunity Program, Biomedicine Institute & Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic., Australia.
FEBS Lett. 2023 May;597(10):1375-1383. doi: 10.1002/1873-3468.14620. Epub 2023 Apr 18.
Spindles are intracellular crystals of the fusolin protein that enhances the oral virulence of insect poxviruses by disruption of the larval chitinous peritrophic matrix. The enigmatic fusolin protein is classified as a lytic polysaccharide monooxygenase (LPMO) by sequence and structure. Although circumstantial evidence points towards a role for fusolin in chitin degradation, no biochemical data exist to verify this claim. In the present study, we demonstrate that fusolin released from over 40-year-old spindles, stored for 10 years at 4 °C, are chitin-degrading LPMOs. Not only was fusolin active after long-term storage, but it also withstood high temperature and oxidative stress in its crystalline form, highlighting extreme stability that is beneficial to viral persistence and desirable for potential biotechnology applications.
纺锤体是 fusolin 蛋白的细胞内晶体，通过破坏幼虫几丁质围食膜基质来增强昆虫痘病毒的口腔毒力。神秘的 fusolin 蛋白在序列和结构上被归类为裂解多糖单加氧酶（LPMO）。尽管间接证据表明 fusolin 在几丁质降解中起作用，但没有生化数据来验证这一说法。在本研究中，我们证明了从超过 40 年的纺锤体中释放的 fusolin，在 4°C 下储存 10 年后，是具有几丁质降解活性的 LPMO。fusolin 不仅在长期储存后仍然具有活性，而且以结晶形式耐受高温和氧化应激，突出了其极端稳定性，这有利于病毒的持续存在，并为潜在的生物技术应用提供了有利条件。
