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Biology subjects

Shamsi, Z.

Publications and source records attributed to Shamsi, Z..

2 recordsLinked to original sources

TLmutation: predicting the effects of mutations using transfer learning

A reoccurring challenge in bioinformatics is predicting the phenotypic consequence of amino acid variation in proteins. With the recent advancements in sequencing techniques, sufficient genomic data has become available to train models that predict the evolutionary statistical energies, but there is still inadequate experimental data to directly predict functional effects. One approach to overcome this data scarcity is to apply transfer learning and train more models with available datasets. In this study, we propose a set of transfer learning algorithms we call TLmutation, which implements a supervised transfer learning algorithm that transfers knowledge from survival data of a protein to a particular function of that protein. This is followed by an unsupervised transfer learning algorithm that extends the knowledge to a homologous protein. We explore the application of our algorithms in three cases. First, we test the supervised transfer on 17 previously published deep mutagenesis datasets to complete and refine missing datapoints. We further investigate these datasets to identify which mutations build better predictors of variant functions. In the second case, we apply the algorithm to predict higher-order mutations solely from single point mutagenesis data. Finally, we perform the unsupervised transfer learning algorithm to predict mutational effects of homologous proteins from experimental datasets. These algorithms are generalized to transfer knowledge between Markov random field models. We show the benefit of our transfer learning algorithms to utilize informative deep mutational data and provide new insights into protein variant functions. As these algorithms are generalized to transfer knowledge between Markov random field models, we expect these algorithms to be applicable to other disciplines.

bioinformatics↗

Concestor kinase activation mechanism uncovers the cyclin dependence of CDK family kinases.

Evolution has altered the free energy landscapes of protein kinases to introduce different regulatory switches and alters their catalytic functions. An understanding of evolutionary pathways behind these changes at atomistic resolution is of great importance for drug design. In this work, we demonstrate how cyclin dependency has emerged in cyclin-dependent kinases (CDKs) by reconstructing their closest experimentally characterized cyclin-independent ancestor. Using available crystal structures of CDK2, regulatory switches are identified and four possible hypotheses describing why CDK2 requires an extra intra-domain regulatory switch compared to the ancestor are formulated. Each hypothesis is tested using all-atom molecular dynamics simulations. Both systems show similar stability in the K33-E51 hydrogen bond and in the alignment of residues in the regulatory-spine, two key protein kinase regulatory elements, while auto-inhibition due to a helical turn in the a-loop is less favorable in the ancestor. The aspartate of the DFG motif does not form a bidentate bond with Mg in CDK2, unlike the ancestor. Using the results of hypothesizes testing, a set of mutations responsible for the changes in CDK2 are identified. Our findings provide a mechanistic rationale for how evolution has added a new regulatory switch to CDK proteins. Moreover, our approach is directly applicable to other proteins.

evolutionary biology↗