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Biomedical subjects

Jamie H D Cate

Publications and source records attributed to Jamie H D Cate.

7 recordsLinked to original sources
PubMed2026

Structure and evolution-guided design of minimal RNA-guided nucleases.

The design of RNA-guided nucleases with properties not limited by evolution can expand programmable genome-editing capabilities. However, generating diverse multidomain proteins with robust enzymatic properties remains challenging. Here, we use a protein design strategy that couples a structure-guided inverse-folding model with evolution-informed residue constraints to generate active, divergent variants of TnpB, a minimal CRISPR-Cas12-like nuclease, termed SynTnpBs. High-throughput screening of artificial intelligence-generated variants yielded editors that retained or exceeded wild-type activity in bacterial, plant, and human cells. Cryo-electron microscopy-based structure determination of the most divergent variant revealed stabilizing contacts in the RNA-DNA interfaces across conformations, demonstrating the design potential of this approach. Together, these results establish a strategy for creating non-natural RNA-guided nucleases and conformationally active nucleic acid binders, enlarging the designable protein space.

Humans↗
PubMed2025

Improving RNA Secondary Structure Prediction Through Expanded Training Data.

In recent years, deep learning has revolutionized protein structure prediction, achieving remarkable speed and accuracy. RNA structure prediction, however, has lagged behind. Although several methods have shown some success in predicting RNA secondary and tertiary structures, none have reached the accuracy observed with contemporary protein models. The lack of success of these RNA structure prediction models has been proposed to be due to limited high-quality structural information that can be used as training data. To probe this proposed limitation, we developed a large and diverse dataset comprising paired RNA sequences and their corresponding secondary structures. We assess the utility of this enhanced dataset by retraining on a deep learning model, SincFold. We find that SincFold exhibited improved generalization to some previously unseen RNA families, enhancing its capability to predict accurate de novo RNA secondary structures. The RNASSTR dataset provides a substantial advance for RNA structure modeling, laying a strong foundation for the development of future RNA secondary structure prediction algorithms.

Journal Article↗
PubMed2006

Structural basis for mRNA and tRNA positioning on the ribosome.

Protein synthesis requires the accurate positioning of mRNA and tRNA in the peptidyl-tRNA site of the ribosome. Here we describe x-ray crystal structures of the intact bacterial ribosome from Escherichia coli in a complex with mRNA and the anticodon stem-loop of P-site tRNA. At 3.5-A resolution, these structures reveal rearrangements in the intact ribosome that clamp P-site tRNA and mRNA on the small ribosomal subunit. Binding of the anticodon stem-loop of P-site tRNA to the ribosome is sufficient to lock the head of the small ribosomal subunit in a single conformation, thereby preventing movement of mRNA and tRNA before mRNA decoding.

Base Sequence↗
PubMed2005

Accessibility of 18S rRNA in human 40S subunits and 80S ribosomes at physiological magnesium ion concentrations--implications for the study of ribosome dynamics.

Protein biosynthesis requires numerous conformational rearrangements within the ribosome. The structural core of the ribosome is composed of RNA and is therefore dependent on counterions such as magnesium ions for function. Many steps of translation can be compromised or inhibited if the concentration of Mg(2+) is too low or too high. Conditions previously used to probe the conformation of the mammalian ribosome in vitro used high Mg(2+) concentrations that we find completely inhibit translation in vitro. We have therefore probed the conformation of the small ribosomal subunit in low concentrations of Mg(2+) that support translation in vitro and compared it with the conformation of the 40S subunit at high Mg(2+) concentrations. In low Mg(2+) concentrations, we find significantly more changes in chemical probe accessibility in the 40S subunit due to subunit association or binding of the hepatitis C internal ribosomal entry site (HCV IRES) than had been observed before. These results suggest that the ribosome is more dynamic in its functional state than previously appreciated.

Humans↗
PubMed2004

Structural basis for the control of translation initiation during stress.

During environmental stress, organisms limit protein synthesis by storing inactive ribosomes that are rapidly reactivated when conditions improve. Here we present structural and biochemical data showing that protein Y, an Escherichia coli stress protein, fills the tRNA- and mRNA-binding channel of the small ribosomal subunit to stabilize intact ribosomes. Protein Y inhibits translation initiation during cold shock but not at normal temperatures. Furthermore, protein Y competes with conserved translation initiation factors that, in bacteria, are required for ribosomal subunit dissociation. The mechanism used by protein Y to reduce translation initiation during stress and quickly release ribosomes for renewed translation initiation may therefore occur widely in nature.

Bacterial Proteins↗
PubMed2004

A conformational switch controls hepatitis delta virus ribozyme catalysis.

Ribozymes enhance chemical reaction rates using many of the same catalytic strategies as protein enzymes. In the hepatitis delta virus (HDV) ribozyme, site-specific self-cleavage of the viral RNA phosphodiester backbone requires both divalent cations and a cytidine nucleotide. General acid-base catalysis, substrate destabilization and global and local conformational changes have all been proposed to contribute to the ribozyme catalytic mechanism. Here we report ten crystal structures of the HDV ribozyme in its pre-cleaved state, showing that cytidine is positioned to activate the 2'-OH nucleophile in the precursor structure. This observation supports its proposed role as a general base in the reaction mechanism. Comparison of crystal structures of the ribozyme in the pre- and post-cleavage states reveals a significant conformational change in the RNA after cleavage and that a catalytically critical divalent metal ion from the active site is ejected. The HDV ribozyme has remarkable chemical similarity to protein ribonucleases and to zymogens for which conformational dynamics are integral to biological activity. This finding implies that RNA structural rearrangements control the reactivity of ribozymes and ribonucleoprotein enzymes.

Binding Sites↗