Accurate de novo design of high-affinity protein-binding macrocycles using deep learning
@nchembio
🚀 Paper published from David Baker!🚀
1.RFpeptides is a deep learning pipeline that enables de novo design of high-affinity macrocyclic peptide binders against diverse protein targets. It leverages a diffusion-based backbone generator (RFdiffusion) and a sequence designer (ProteinMPNN) with integrated DL and physics-based scoring.
2.The method succeeded in designing macrocycles that bind four distinct proteins (MCL1, MDM2, GABARAP, and RbtA) with medium to high affinity, testing only ~20 designs per target—orders of magnitude fewer than conventional display-based methods.
3.The standout binder, RBB_D10, targets a flat, previously uncharacterized site on Rhombotarget A (RbtA) with a dissociation constant (Kd) of 9.4 nM, despite starting from a predicted structure. The crystal structure of the complex closely matched the design model (Cα RMSD: 1.4 Å).
4.For GABARAP, two macrocycles (GAB_D8 and GAB_D23) exhibited Kd values of 6 nM and 36 nM, and IC50s of 0.7 nM and 2.5 nM in a competitive AlphaScreen assay—among the highest reported affinities for this target class.
5.Crystal structures for macrocycle–protein complexes (MCL1, GABARAP, RbtA) revealed close agreement with the design models, with RMSDs typically under 1.5 Å, validating the atomic accuracy of RFpeptides-generated binders.
6.Unlike traditional approaches, RFpeptides does not require known ligands or templates. It can target specific patches on proteins, including flat or non-canonical binding sites, by guiding the design via user-defined hotspots.
7.Binders adopt a range of structural topologies—α-helices for MCL1 and MDM2, β-sheets for GABARAP, and loop-like conformations for RbtA—demonstrating the structural diversity achievable with the pipeline.
8.Filtering of candidates combines DL-based (iPAE, pLDDT) and physics-based (ddG, SAP, CMS) metrics, followed by clustering and selection based on structural diversity, enabling rational downselection from tens of thousands of in silico models.
9.Even in the absence of explicit solubility constraints during design, successful binders exhibited good aqueous solubility, increasing the feasibility of downstream development.
10.RFpeptides achieves higher success rates and binding accuracy than any prior peptide design method tested, and allows structure-guided optimization without needing experimentally determined complex structures.
11.The approach opens the door to scalable, customizable design of macrocycles for therapeutics and diagnostics—potentially spanning intracellular targets, flat epitopes, or challenging pathogens with no structural data.
💻Code:
doi.org/10.5281/zenodo.15264…
📜Paper:
nature.com/articles/s41589-0…
#ProteinDesign #Macrocycles #DeepLearning #DeNovoDesign #ComputationalBiology #PeptideTherapeutics