Biology subjects

Smith, T. G.

Publications and source records attributed to Smith, T. G..

4 recordsLinked to original sources

bioRxiv2026

Bivalent Inhibitor Development for a Dynamic Epigenetic Tandem Reader Protein Using a Combinatorial Histone Code

Epigenetic readers are a class of proteins that recognize specific chemical modifications on histones to differentially regulate gene expression. Aberrant expression of readers can drive the progression of many diseases and cancers, making this protein class viable therapeutic targets. Understanding the landscape of histone modifications recognized by reader domains, and the structural mechanisms that drive these molecular recognition events, is crucial for guiding the design of pharmaceutically relevant chemical probes. BPTF contains a plant homeodomain (PHD) finger and tandem bromodomain (BRD). Here, we expand upon previous studies that found the BPTF BRD can engage acetyllysine modifications on the N-terminus of histone H3. We uncover H3K4me3K14ac as the specific modifications recognized by the PHD BRD cassette, which is confirmed by crystallography. Using orthogonal methods, our work explores how these modifications can be read cooperatively, including in cis. We report the first experimental evidence proposing a ligand-induced conformational change between the two reader domains of BPTF, supporting previous computational approaches that have predicted a macromolecular rearrangement. We leverage these structural insights to rationally design a peptide-small molecule conjugate MJ-1 that inhibits both domains of BPTF and overcomes ligandability challenges associated with PHD-finger-containing proteins. The results presented here elucidate the molecular basis of the bivalent recognition of multiply modified histone H3 by BPTF and provide structural insight for developing compounds targeting the PHD finger of BPTF for therapeutic applications.

biochemistry↗

bioRxiv2025

Sequential oxidation of L-lysine by a non-heme iron hydroxylase

2-oxoglutarate-dependent non-heme iron hydroxylases offer a direct route to functionalizing C(sp3)-H bonds across a diverse range of substrates, making them prime candidates for chemoenzymatic synthetic strategies. We demonstrate the ability of a non-heme iron L-lysine dioxygenase to perform sequential oxidation and computationally explore structural elements that promote this reactivity.

biochemistry↗

bioRxiv2021

Sensitive identification of known and unknown protease activities by unsupervised linear motif deconvolution

The cleavage-site specificities for many proteases are not well-understood, restricting the utility of supervised classification methods. We present an algorithm and web interface to overcome this limitation through the unsupervised detection of overrepresented patterns in protein sequence data, providing insight into the mixture of protease activities contributing to a complex system. Here, we apply the RObust LInear Motif Deconvolution (RoLiM) algorithm to confidently detect substrate cleavage patterns for SARS-CoV-2 Mpro protease in N terminome data of an infected human cell line. Using mass spectrometry-based peptide data from a case-control comparison of 341 primary urothelial bladder cancer cases and 110 controls, we identified distinct sequence motifs indicative of increased MMP activity in urine from cancer patients. Evaluation of N terminal peptides from patient plasma post-chemotherapy detected novel Granzyme B/Corin activity. RoLiM will enhance unbiased investigation of peptide sequences to establish the composition of known and uncharacterized protease activities in biological systems.

bioinformatics↗

bioRxiv2019

PDX models reflect the proteome landscape of pediatric acute lymphoblastic leukemia but divert in select pathways

Murine xenografts of pediatric leukemia are known to accurately recapitulate genomic aberrations. How this translates to the functional capacity of the proteome is unknown. Here, we studied global protein abundance, phosphorylation, and proteolytic processing in 11 pediatric B- and T-cell acute lymphoblastic leukemia patients and 19 corresponding xenografts. Protein level differences that stratified pediatric disease subtypes at diagnostic and relapse stages were largely recapitulated in xenograft models. Patient xenografts lacked multiple human leukocyte antigens, and complement proteins, and presented incomplete response mechanisms to the host immune system which is absent in the murine model. The dominant expression of MKI67 and cell cycle proteins indicated a high proliferative capacity of xenografted cells residing in the spleen. Structural genomic changes and mutations found in patients were reflected at the protein level. The post-translational modification landscape is shaped by leukemia type and host and only to a limited degree by the patient of origin. This study portrays how genomic and host factors shape protein and post-translational modification landscapes differently, and confirms murine patient-derived xenograft as competent model system while highlighting important areas of diverging biology.

cancer biology↗