Computational Structural Biology Lab · IBG, Izmir

How biomolecular interfaces form, persist and change

We combine AlphaFold-based sampling, molecular dynamics and integrative modelling to assess the accuracy of predicted assemblies, resolve the interface contacts that determine their binding specificity, and extract conformational dynamics from sequence-derived information such as AlphaFold distograms.

Research

Our research moves from static to dynamic views of biomolecular interfaces: we test how reliably they can be predicted, map how mutations rewire them, resolve which persistent contacts govern binding, and ask how much of this behaviour is encoded in sequence.

Benchmarking predictors

How reliable are structure and affinity predictions?

Interface change

Which mutations rewire an interface?

Interface dynamics

Which persistent contacts decide partner choice and function?

Dynamics in sequence

How much of an interface’s motion is written in its sequence?

feeds back into prediction

  • Hydrogen bond (dashed) ×3
  • Salt bridge (solid) ×3
  • Hydrophobic contact (dotted) ×7
  • Line weight: transient → persistent
XRCC1–DNA polymerase β interface (PDB 3K75): 13 contacts traced across a 200‑frame DynaBench trajectory with DynaPIN, each drawn by its persistence (share of frames in which the contact exists, 18–100%).

Benchmarking predictors

AlphaFold-based pipelines model most assemblies well, but not all. Through CASP, CAPRI and dedicated benchmarks, we test how far structure and affinity predictors can be trusted, and build leaner sampling and scoring protocols.

Interface change

A static interface already shows which positions matter. We map how mutations, disease variants and isoforms strengthen, weaken or abolish interfaces, and use these maps for functional characterisation or to redesign binders.

Interface dynamics

Many interface contacts are transient, and the ones that persist govern binding. We quantify contact persistence from simulations and compare related complexes to find the dynamic networks behind partner choice and function.

Software

Open-source tools from the lab, with code released on GitHub.

  • PROT-ON

    Structure-based detection of designer mutations at protein–protein interfaces. PROT-ON scans every interface position with EvoEF1 or FoldX (the web server runs EvoEF1), flags outlier mutations with an interquartile-range threshold, and filters them for stability and, optionally, evolutionary likelihood (PSSM) to propose mutations that strengthen or abolish binding. A web run takes under 10 minutes per partner. Test cases include MDM2–p53, ACE2–spike and MCL1–NOXA. Web serverUsage statisticsRepositoryPaper

    Try it in a HADDOCK tutorial

    PROT-ON is part of the official HADDOCK antibody–antigen tutorials, where it scans the docked interface for mutations that improve binding and helps identify an optimal binder sequence.

  • DynaPIN

    Dynamic interface fingerprints from MD trajectories or structure ensembles: quality control, residue properties and interaction networks in one command.Repository
  • MinnieFold

    A 50-fold reduced version of massive AlphaFold2 sampling with custom ranking, for antibody–antigen and other complexes with shallow alignments.Repository
  • DistoFlex

    Reads flexibility from AlphaFold2 and AlphaFold3 distograms by locating multimodal residue-pair distance distributions.Repository

Team

Ezgi Karaca

Principal Investigator

Ezgi Karaca

ez-ghee kah-rah-jah

Group Leader, Izmir Biomedicine and Genome Center · Associate Professor and Head of the Molecular Biology and Genetics Program, Dokuz Eylül University

Ezgi trained in chemical engineering at Boğaziçi University and did her PhD with Alexandre Bonvin at Utrecht University, where she became a long-time contributor to the HADDOCK integrative modelling platform. As a Humboldt postdoctoral fellow at EMBL Heidelberg she worked on integrative structure determination of molecular machines, before starting her group at IBG in 2017 with a Humboldt return fellowship.

She was an assessor of protein assemblies in CASP14 and CASP15, received the Science Academy Young Scientist Award (BAGEP) in 2020, and is the BioExcel Ambassador for Türkiye.

Burcu Özden
Burcu Özden
boor-joo urz-den
Researcher, PhD ORCID
  • PhD, Molecular Biology and Genetics, Izmir International Biomedicine and Genome Institute (2024)
  • MSc, Chemical Engineering, Boğaziçi University (2018)
  • BSc, Chemical Engineering, Boğaziçi University (2015)
Buse Şahin
Buse Şahin
boo-seh shah-heen
PhD student ORCID
  • MSc, Molecular Biology and Genetics, Izmir International Biomedicine and Genome Institute (2025)
  • BSc, Bioinformatics and Genetics, Kadir Has University (2023)
Ecem Sekkin
Ecem Sekkin
eh-jem sek-keen
PhD student ORCID
  • MSc, Chemistry, Middle East Technical University (2024)
  • BSc, Chemistry, Middle East Technical University (2022)
Murat Taylan Şahin
Murat Taylan Şahin
moo-raht tie-lahn shah-heen
Research assistant, MSc student ORCID
  • BSc, Computer Engineering, Dokuz Eylül University (2022)

Funding and partners

  • 2027–BioExcel-4 — Centre of Excellence for computational biomolecular researchEuroHPC Joint Undertaking · IBG partner in the KTH-coordinated consortium
  • 2026–AF-ANM — AlphaFold distogram-driven anisotropic network modelsTÜBİTAK 1001
  • 2026–CDKure — CDK8/19 inhibitors to restore erythropoiesis in Diamond–Blackfan anaemiaERDERA Joint Transnational Call · IBG partner in the CDKure collaborative consortium
  • 2025–AF-Ensemble — AlphaFold-generated conformational ensembles of protein complexesTÜBİTAK–Campus France · with Marc Lensink, CNRS, Lille
  • 2023–25DynaBench — Dynamics of protein–protein interfacesTÜBİTAK–Campus France · with Sophie Sacquin-Mora and Chantal Prévost, CNRS, Paris
  • 2020–27EMBO Installation Grant — Pioneer transcription factor binding modes to chromatinEMBO

Computations run on MareNostrum 5 at the Barcelona Supercomputing Center, through Türkiye’s EuroHPC partnership, and on in-house GPU workstations.

Talks and outreach

Invited talks, 2025–26

Online outreach

Supervised theses

Three PhD and seven MSc theses supervised as main advisor.

Doctoral theses

  • 2026Büşra Savaş — Benchmarking AlphaFold for predicting protein interactions and their dynamics, full text
  • 2024Burcu Özden — Assessment of the protein assembly modeling strategies, full text
  • 2024Ayşe Berçin Barlas Yılmaz — Understanding the function of biomolecular complexes through the lens of molecular dynamics, full text

Master’s theses

  • 2026Ayris Doldur — Wwox structure and mutational effects
  • 2025Buse Şahin — Human–parasite interactions with AlphaFold
  • 2022Eda Şamiloğlu — Binding affinity predictors on spike–ACE2
  • 2022Mehdi Koşaca — PROT-ON interface redesign
  • 2021Büşra Savaş — Working principles of DNMT3A
  • 2020Deniz Doğan — DNA methylation mechanisms
  • 2019Tülay Karakulak — Ligand specificity of TAM receptors

Contact

We welcome students and postdocs interested in structure prediction, molecular dynamics and protein interfaces. Send Ezgi a short note on your interests, with a CV.

Email
ezgi.karaca@ibg.edu.tr
Code
github.com/CSB-KaracaLab
Scholar
Full publication list on Google Scholar
Updates
Ezgi on LinkedIn (lab news)
Address
Izmir Biomedicine and Genome Center, Dokuz Eylül University Health Campus, Balçova 35340, Izmir, Türkiye