Biology subjects

Domecillo, M.

Publications and source records attributed to Domecillo, M..

4 recordsLinked to original sources

bioRxiv2026

Designing enzymes for new-to-nature chemistry and non-natural substrates with AlphaProtein Novo

Creating highly active enzymes for arbitrary reactions is a transformative goal for the molecular sciences (1). Traditional protein engineering (2,3) is constrained by a reliance on existing natural starting points, which are often challenging to discover. De novo design offers the potential to overcome this by creating enzymes from first principles (4), but has yet to achieve practically relevant catalytic properties. Here we present AlphaProtein Novo (AP Novo), a machine-learning pipeline that demonstrates, for the first time, that de novo enzyme design can outperform natural sequence mining in addressing challenging chemistry. We used AP Novo to design new-to-nature nitrene transferases to synthesise the pharmacophore piperidine with unprecedented product selectivity, and to create enzymes that degrade the environmental toxin DEHP under conditions that denature natural enzymes. We also obtained state-of-the-art catalytic efficiencies on two well-studied model reactions, and through iterative design and analysis found that key enablers of success were mechanism-inspired metrics based on AlphaFold 3 predictions and sequence-ensemble-based scoring of designed backbones. Our results show that de novo design has become a powerful complement to natural enzyme diversity for discovering catalysts for a range of applications.

synthetic biology↗

bioRxiv2026

De novo design of transmembrane accessory subunits for fold stabilization and expansion

Transmembrane (TM) proteins play essential roles in biology as transporters, ion channels, chaperones, enzymes, and mediators of signal transduction. However, membrane proteins often suffer from inefficient folding and intrinsic instability. Misfolding in cells can cause numerous loss-of-function pathologies. Likewise, denaturation upon purification in the laboratory is a critical barrier to structure determination and characterization of key biochemical mechanisms. Generalizable strategies to stabilize membrane proteins remain limited. Here, we developed an informatics-based de novo design strategy to create synthetic auxiliary subunits that interact with the TM helices of a model pentameric ion channel, thereby bolstering folding while maintaining channel function. Biochemical and structural characterization reveal the synthetic TM subunits can also be used to create larger multi-spanning designer proteins of custom topology. This proof-of-concept motivates the feasibility of computationally designed accessory TM helices as potential pharmacological chaperone "folding correctors" of membrane proteins in disease and as tools in structural biology.

biochemistry↗

bioRxiv2026

Principles of in situ protein sequencing: expansion microscopy-adapted Edman degradation and amino acid recognition

The ability to map protein identity, with resolution sufficient to infer interactions, would support analysis of how proteins work together, or malfunction, in biological processes and diseases. Although several emerging technologies aim towards single-molecule protein sequencing, they require proteins to be removed from the nanoscale spatial context of cells and tissues. Expansion microscopy (ExM) has facilitated a diversity of chemical analyses by isotropically separating molecules throughout a specimen after permeation via a charged hydrogel, followed by gel swelling. Here, we adapt key protein sequencing steps - Edman degradation and amino acid recognition - to the ExM gel context. Using testbed peptides in ExM gels, we show that N-terminal amino acids can be recognized over multiple cycles of in-gel Edman degradation. This principle-oriented study demonstrates sequencing chemistry on defined synthetic constructs, rather than endogenous proteins in biological samples. These results establish principles of in situ protein sequencing and provide a framework for future in situ protein sequencing developments, including the development of higher specificity and affinity amino acid binders.

biochemistry↗

bioRxiv2024

MreC-MreD structure reveals a multifaceted interface that controls MreC conformation

The peptidoglycan (PG) cell wall is critical for bacterial growth and survival and is a primary antibiotic target. MreD is an essential accessory factor of the Rod complex, which carries out PG synthesis during elongation, yet little is known about how MreD facilitates this process. Here, we present the cryo-electron microscopy structure of Thermus thermophilus MreD in complex with another essential Rod complex component, MreC. The structure reveals that a periplasmic-facing pocket of MreD interacts with multiple membrane-proximal regions of MreC. We use single-molecule FRET to show that MreD controls the conformation of MreC through these contacts, inducing a state primed for Rod complex activation. Using E. coli as a model, we demonstrate that disrupting these interactions abolishes Rod complex activity in vivo. Our findings reveal the role of MreD in bacterial cell shape determination and highlight its potential as an antibiotic target.

microbiology↗