Wang H, Planchart A, Stubbs G
Department of Molecular Biology, Vanderbilt University, Nashville, Tennessee 37235, USA.
Biophys J. 1998 Jan;74(1):633-8. doi: 10.1016/S0006-3495(98)77822-1.
Carboxylate groups have been known for many years to drive the disassembly of simple viruses, including tobacco mosaic virus (TMV). The identities of the carboxylate groups involved and the mechanism by which they initiate disassembly have not, however, been clear. Structures have been determined at resolutions between 2.9 and 3.5 A for five tobamoviruses by fiber diffraction methods. Site-directed mutagenesis has also been used to change numerous carboxylate side chains in TMV to the corresponding amides. Comparison of the stabilities of the various mutant viruses shows that disassembly is driven by a much more complex set of carboxylate interactions than had previously been postulated. Despite the importance of the carboxylate interactions, they are not conserved during viral evolution. Instead, it appears that during evolution, patches of electrostatic interaction drift across viral subunit interfaces. The flexibility of these interactions confers a considerable advantage on the virus, enabling it to change its surface structure rapidly and thus evade host defenses.
多年来，人们已知羧基可促使包括烟草花叶病毒（TMV）在内的简单病毒解体。然而，所涉及的羧基的身份以及它们引发解体的机制尚不清楚。通过纤维衍射方法，已确定了五种烟草花叶病毒在2.9至3.5埃分辨率下的结构。定点诱变也被用于将TMV中的许多羧基侧链改变为相应的酰胺。对各种突变病毒稳定性的比较表明，解体是由一组比先前假设更为复杂的羧基相互作用驱动的。尽管羧基相互作用很重要，但它们在病毒进化过程中并不保守。相反，在进化过程中，静电相互作用区域似乎在病毒亚基界面上漂移。这些相互作用的灵活性赋予了病毒相当大的优势，使其能够迅速改变其表面结构，从而逃避宿主防御。
