Given the task definition and input, reply with output. In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

Cellular and viral S-adenosylmethionine-dependent methyltransferases are involved in many regulated processes such as metabolism, detoxification, signal transduction, chromatin remodeling, nucleic acid processing, and mRNA capping. The Severe Acute Respiratory Syndrome coronavirus nsp16 protein is a S-adenosylmethionine-dependent (nucleoside-29-O)methyltransferase only active in the presence of its activating partner nsp10. We report the nsp10/nsp16 complex structure at 2.0 A resolution, which shows nsp10 bound to nsp16 through a ,930 A 2 surface area in nsp10. Functional assays identify key residues involved in nsp10/nsp16 association, and in RNA binding or catalysis, the latter likely through a SN2-like mechanism. We present two other crystal structures, the inhibitor Sinefungin bound in the S-adenosylmethionine binding pocket and the tighter complex nsp10(Y96F)/nsp16, providing the first structural insight into the regulation of RNA capping enzymes in (+)RNA viruses. Citation: Decroly E, Debarnot C, Ferron F, Bouvet M, Coutard B, et al. (2011) Crystal Structure and Functional Analysis of the SARS-Coronavirus RNA Cap 29-O-Methyltransferase nsp10/nsp16 Complex. PLoS Pathog 7(5): e1002059.
Crystal Structure and Functional Analysis of the SARS- Coronavirus RNA Cap 29-O-Methyltransferase nsp10/ nsp16 Complex