S-PLUS: LEnticular Galaxies in Stripe 82 (LEGS82).

This work is a Brazilian-Indian collaboration. It aims at investigating the structural properties of Lenticular galaxies in the Stripe 82 using a combination of S-PLUS (Southern Photometric Local Universe Survey) and SDSS data. S-PLUS is a novel optical multi-wavelength survey which will cover nearly 8000 square degrees of the Southern hemisphere in the next years and the first data release covers the Stripe 82 area. The morphological classification and study of the galaxies' stellar population will be performed combining the Bayesian Spectral type (from BPZ) and Morfometryka (MFMTK) parameters. BPZ and MFMTK are two complementary techniques, since the first one determines the most likely stellar population of a galaxy, in order to obtain its photometric redshift (phot-z), and the second one recovers non-parametric morphological quantities, such as asymmetries and concentration. The combination of the two methods allows us to explore the correlation between galaxies shapes (smooth, with spiral arms, etc.) and their stellar contents (old or young population). The preliminary results, presented in this work, show how this novel data set opens a new window on our understanding of the nearby universe.

Site-specific and regiospecific installation of methylarginine analogues into recombinant histones and insights into effector protein binding.

Arginine methylation has emerged as a widespread post-translational modification with influence over myriad cellular processes. However, the molecular mechanisms underlying such methylarginine-dependent phenomena remain unclear. To aid in this research, a facile method was developed to install methylarginine analogues on recombinant protein for use in biochemical, biophysical, and structural studies. Through chemical conjugation of novel α,ß-unsaturated amidine precursors with proteins, methylarginine mimics can be displayed with control of methylation site, extent, and regiospecificity. Analogue installation into histones using this strategy produced modified proteins that were recognized by antibodies specific to endogenous methylarginine, and these histones retained the capacity to form mononucleosomes. Moreover, a native methylarginine-specific binding domain was shown to interact with methylarginine analogue-modified substrates. This chemical conjugation method for installing methylarginine analogues provides an efficient route to produce homogeneous modified proteins for subsequent investigations of methylarginine-dependent processes.

Chemical genetic strategy for targeting protein kinases based on covalent complementarity.

The conserved nature of the ATP-binding site of the > 500 human kinases renders the development of specific inhibitors a challenging task. A widely used chemical genetic strategy to overcome the specificity challenge exploits a large-to-small mutation of the gatekeeper residue (a conserved hydrophobic amino acid) and the use of a bulky inhibitor to achieve specificity via shape complementarity. However, in a number of cases, introduction of a glycine or alanine gatekeeper results in diminished kinase activity and ATP affinity. A new chemical genetic approach based on covalent complementarity between an engineered gatekeeper cysteine and an electrophilic inhibitor was developed to address these challenges. This strategy was evaluated with Src, a proto-oncogenic tyrosine kinase known to lose some enzymatic activity using the shape complementarity chemical genetic strategy. We found that Src with a cysteine gatekeeper recapitulates wild type activity and can be irreversibly inhibited both in vitro and in cells. A cocrystal structure of T338C c-Src with a vinylsulfonamide-derivatized pyrazolopyrimidine inhibitor was solved to elucidate the inhibitor binding mode. A panel of electrophilic inhibitors was analyzed against 307 kinases and MOK (MAPK/MAK/MRK overlapping kinase), one of only two human kinases known to have an endogenous cysteine gatekeeper. This analysis revealed remarkably few off-targets, making these compounds the most selective chemical genetic inhibitors reported to date. Protein engineering studies demonstrated that it is possible to increase inhibitor potency through secondary-site mutations. These results suggest that chemical genetic strategies based on covalent complementarity should be widely applicable to the study of protein kinases.