The HIV-1 Tat Protein Is Monomethylated at Lysine 71 by the Lysine Methyltransferase KMT7.

The HIV-1 transactivator protein Tat is a critical regulator of HIV transcription primarily enabling efficient elongation of viral transcripts. Its interactions with RNA and various host factors are regulated by ordered, transient post-translational modifications. Here, we report a novel Tat modification, monomethylation at lysine 71 (K71).

Sulfur-Oxygen Chalcogen Bonding Mediates AdoMet Recognition in the Lysine Methyltransferase SET7/9.

Recent studies have demonstrated that carbon-oxygen (CH···O) hydrogen bonds have important roles in S-adenosylmethionine (AdoMet) recognition and catalysis in methyltransferases. Here, we investigate noncovalent interactions that occur between the AdoMet sulfur cation and oxygen atoms in methyltransferase active sites. These interactions represent sulfur-oxygen (S···O) chalcogen bonds in which the oxygen atom donates a lone pair of electrons to the σ antibonding orbital of the AdoMet sulfur atom.

Calmodulin Methyltransferase Is Required for Growth, Muscle Strength, Somatosensory Development and Brain Function.

Calmodulin lysine methyl transferase (CaM KMT) is ubiquitously expressed and highly conserved from plants to vertebrates. CaM is frequently trimethylated at Lys-115, however, the role of CaM methylation in vertebrates has not been studied. CaM KMT was found to be homozygously deleted in the 2P21 deletion syndrome that includes 4 genes.

Measurement of the Bs(0)→μ+ μ- branching fraction and search for B(0)→μ+ μ- with the CMS experiment.

Results are presented from a search for the rare decays Bs(0)→μ+ μ- and B(0)→μ+ μ- in pp collisions at sqrt[s]=7 and 8 TeV, with data samples corresponding to integrated luminosities of 5 and 20  fb(-1), respectively, collected by the CMS experiment at the LHC. An unbinned maximum-likelihood fit to the dimuon invariant mass distribution gives a branching fraction B(Bs(0)→μ+ μ-)=(3.0(-0.

Manipulating unconventional CH-based hydrogen bonding in a methyltransferase via noncanonical amino acid mutagenesis.

Recent studies have demonstrated that the active sites of S-adenosylmethionine (AdoMet)-dependent methyltransferases form strong carbon-oxygen (CH···O) hydrogen bonds with the substrate's sulfonium group that are important in AdoMet binding and catalysis. To probe these interactions, we substituted the noncanonical amino acid p-aminophenylalanine (pAF) for the active site tyrosine in the lysine methyltransferase SET7/9, which forms multiple CH···O hydrogen bonds to AdoMet and is invariant in SET domain enzymes. Using quantum chemistry calculations to predict the mutation's effects, coupled with biochemical and structural studies, we observed that pAF forms a strong CH···N hydrogen bond to AdoMet that is offset by an energetically unfavorable amine group rotamer within the SET7/9 active site that hinders AdoMet binding and activity.