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Agarwal V, McShan AC. The power and pitfalls of AlphaFold2 for structure prediction beyond rigid globular proteins. Nat Chem Biol 2024:10.1038/s41589-024-01638-w. [PMID: 38907110 DOI: 10.1038/s41589-024-01638-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 04/29/2024] [Indexed: 06/23/2024]
Abstract
Artificial intelligence-driven advances in protein structure prediction in recent years have raised the question: has the protein structure-prediction problem been solved? Here, with a focus on nonglobular proteins, we highlight the many strengths and potential weaknesses of DeepMind's AlphaFold2 in the context of its biological and therapeutic applications. We summarize the subtleties associated with evaluation of AlphaFold2 model quality and reliability using the predicted local distance difference test (pLDDT) and predicted aligned error (PAE) values. We highlight various classes of proteins that AlphaFold2 can be applied to and the caveats involved. Concrete examples of how AlphaFold2 models can be integrated with experimental data in the form of small-angle X-ray scattering (SAXS), solution NMR, cryo-electron microscopy (cryo-EM) and X-ray diffraction are discussed. Finally, we highlight the need to move beyond structure prediction of rigid, static structural snapshots toward conformational ensembles and alternate biologically relevant states. The overarching theme is that careful consideration is due when using AlphaFold2-generated models to generate testable hypotheses and structural models, rather than treating predicted models as de facto ground truth structures.
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Affiliation(s)
- Vinayak Agarwal
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA.
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
| | - Andrew C McShan
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA.
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2
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Feng RR, Wang M, Zhang W, Gai F. Unnatural Amino Acids for Biological Spectroscopy and Microscopy. Chem Rev 2024; 124:6501-6542. [PMID: 38722769 DOI: 10.1021/acs.chemrev.3c00944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
Abstract
Due to advances in methods for site-specific incorporation of unnatural amino acids (UAAs) into proteins, a large number of UAAs with tailored chemical and/or physical properties have been developed and used in a wide array of biological applications. In particular, UAAs with specific spectroscopic characteristics can be used as external reporters to produce additional signals, hence increasing the information content obtainable in protein spectroscopic and/or imaging measurements. In this Review, we summarize the progress in the past two decades in the development of such UAAs and their applications in biological spectroscopy and microscopy, with a focus on UAAs that can be used as site-specific vibrational, fluorescence, electron paramagnetic resonance (EPR), or nuclear magnetic resonance (NMR) probes. Wherever applicable, we also discuss future directions.
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Affiliation(s)
- Ran-Ran Feng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Manxi Wang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Feng Gai
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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3
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Bermejo GA, Tjandra N, Clore GM, Schwieters CD. Xplor-NIH: Better parameters and protocols for NMR protein structure determination. Protein Sci 2024; 33:e4922. [PMID: 38501482 PMCID: PMC10962493 DOI: 10.1002/pro.4922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 01/26/2024] [Accepted: 01/28/2024] [Indexed: 03/20/2024]
Abstract
The present work describes an update to the protein covalent geometry and atomic radii parameters in the Xplor-NIH biomolecular structure determination package. In combination with an improved treatment of selected non-bonded interactions between atoms three bonds apart, such as those involving methyl hydrogens, and a previously developed term that affects the system's gyration volume, the new parameters are tested using structure calculations on 30 proteins with restraints derived from nuclear magnetic resonance data. Using modern structure validation criteria, including several formally adopted by the Protein Data Bank, and a clear measure of structural accuracy, the results show superior performance relative to previous Xplor-NIH implementations. Additionally, the Xplor-NIH structures compare favorably against originally determined NMR models.
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Affiliation(s)
- Guillermo A. Bermejo
- Laboratory of Chemical PhysicsNational Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaMarylandUSA
| | - Nico Tjandra
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of HealthBethesdaMarylandUSA
| | - G. Marius Clore
- Laboratory of Chemical PhysicsNational Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaMarylandUSA
| | - Charles D. Schwieters
- Laboratory of Chemical PhysicsNational Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaMarylandUSA
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4
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Zeballos N, Comino N, Andrés-Sanz D, Santiago-Arcos J, Azkargorta M, Elortza F, Diamanti E, López-Gallego F. Region-Directed Enzyme Immobilization through Engineering Protein Surface with Histidine Clusters. ACS APPLIED MATERIALS & INTERFACES 2024; 16:833-846. [PMID: 38135284 PMCID: PMC10788835 DOI: 10.1021/acsami.3c15993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/22/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023]
Abstract
Enzyme immobilization is a key enabling technology for a myriad of industrial applications, yet immobilization science is still too empirical to reach highly active and robust heterogeneous biocatalysts through a general approach. Conventional protein immobilization methods lack control over how enzymes are oriented on solid carriers, resulting in negative conformational changes that drive enzyme deactivation. Site-selective enzyme immobilization through peptide tags and protein domains addresses the orientation issue, but this approach limits the possible orientations to the N- and C-termini of the target enzyme. In this work, we engineer the surface of two model dehydrogenases to introduce histidine clusters into flexible regions not involved in catalysis, through which immobilization is driven. By varying the position and the histidine density of the clusters, we create a small library of enzyme variants to be immobilized on different carriers functionalized with different densities of various metal chelates (Co2+, Cu2+, Ni2+, and Fe3+). We first demonstrate that His-clusters can be as efficient as the conventional His-tags in immobilizing enzymes, recovering even more activity and gaining stability against some denaturing agents. Furthermore, we find that the enzyme orientation as well as the type and density of the metal chelates affect the immobilization parameters (immobilization yield and recovered activity) and the stability of the immobilized enzymes. According to proteomic studies, His-clusters enable a different enzyme orientation as compared to His-tag. Finally, these oriented heterogeneous biocatalysts are implemented in batch reactions, demonstrating that the stability achieved by an optimized orientation translates into increased operational stability.
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Affiliation(s)
- Nicoll Zeballos
- Center
for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Paseo Miramon 194, 20014 San Sebastián, Spain
| | - Natalia Comino
- Center
for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Paseo Miramon 194, 20014 San Sebastián, Spain
| | - Daniel Andrés-Sanz
- Center
for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Paseo Miramon 194, 20014 San Sebastián, Spain
| | - Javier Santiago-Arcos
- Center
for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Paseo Miramon 194, 20014 San Sebastián, Spain
| | - Mikel Azkargorta
- Center
for Cooperative Research in Biology (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, 800 Bld, 48160 Derio, Bizkaia, Spain
- Centro
de Investigación Biomédica en Red de Enfermedades Hepáticas
y Digestivas (CIBERehd), 28029 Madrid, Spain
| | - Felix Elortza
- Center
for Cooperative Research in Biology (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, 800 Bld, 48160 Derio, Bizkaia, Spain
- Centro
de Investigación Biomédica en Red de Enfermedades Hepáticas
y Digestivas (CIBERehd), 28029 Madrid, Spain
| | - Eleftheria Diamanti
- Center
for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Paseo Miramon 194, 20014 San Sebastián, Spain
| | - Fernando López-Gallego
- Center
for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Paseo Miramon 194, 20014 San Sebastián, Spain
- Ikerbasque,
Basque Foundation for Science, 48013 Bilbao, Spain
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5
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Querci L, Grifagni D, Trindade IB, Silva JM, Louro RO, Cantini F, Piccioli M. Paramagnetic NMR to study iron sulfur proteins: 13C detected experiments illuminate the vicinity of the metal center. JOURNAL OF BIOMOLECULAR NMR 2023; 77:247-259. [PMID: 37853207 PMCID: PMC10687126 DOI: 10.1007/s10858-023-00425-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 09/25/2023] [Indexed: 10/20/2023]
Abstract
The robustness of NMR coherence transfer in proximity of a paramagnetic center depends on the relaxation properties of the nuclei involved. In the case of Iron-Sulfur Proteins, different pulse schemes or different parameter sets often provide complementary results. Tailored versions of HCACO and CACO experiments significantly increase the number of observed Cα/C' connectivities in highly paramagnetic systems, by recovering many resonances that were lost due to paramagnetic relaxation. Optimized 13C direct detected experiments can significantly extend the available assignments, improving the overall knowledge of these systems. The different relaxation properties of Cα and C' nuclei are exploited in CACO vs COCA experiments and the complementarity of the two experiments is used to obtain structural information. The two [Fe2S2]+ clusters containing NEET protein CISD3 and the one [Fe4S4]2+ cluster containing HiPIP protein PioC have been taken as model systems. We show that tailored experiments contribute to decrease the blind sphere around the cluster, to extend resonance assignment of cluster bound cysteine residues and to retrieve details on the topology of the iron-bound ligand residues.
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Affiliation(s)
- Leonardo Querci
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Deborah Grifagni
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Inês B Trindade
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Av. da República (EAN), 2780-157, Oeiras, Portugal
- Division of Biology and Biological Engineering, California Institute of Technology, CA 91125, Pasadena, USA
| | - José Malanho Silva
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Ricardo O Louro
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Av. da República (EAN), 2780-157, Oeiras, Portugal
| | - Francesca Cantini
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Mario Piccioli
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.
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Vitali V, Ackermann K, Hagelueken G, Bode BE. Spectroscopically Orthogonal Labelling to Disentangle Site-Specific Nitroxide Label Distributions. APPLIED MAGNETIC RESONANCE 2023; 55:187-205. [PMID: 38357007 PMCID: PMC10861635 DOI: 10.1007/s00723-023-01611-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/23/2023] [Accepted: 08/25/2023] [Indexed: 02/16/2024]
Abstract
Biomolecular applications of pulse dipolar electron paramagnetic resonance spectroscopy (PDS) are becoming increasingly valuable in structural biology. Site-directed spin labelling of proteins is routinely performed using nitroxides, with paramagnetic metal ions and other organic radicals gaining popularity as alternative spin centres. Spectroscopically orthogonal spin labelling using different types of labels potentially increases the information content available from a single sample. When analysing experimental distance distributions between two nitroxide spin labels, the site-specific rotamer information has been projected into the distance and is not readily available, and the contributions of individual labelling sites to the width of the distance distribution are not obvious from the PDS data. Here, we exploit the exquisite precision of labelling double-histidine (dHis) motifs with CuII chelate complexes. The contribution of this label to the distance distribution widths in model protein GB1 has been shown to be negligible. By combining a dHis CuII labelling site with cysteine-specific nitroxide labelling, we gather insights on the label rotamers at two distinct sites, comparing their contributions to distance distributions based on different in silico modelling approaches and structural models. From this study, it seems advisable to consider discrepancies between different in silico modelling approaches when selecting labelling sites for PDS studies. Supplementary Information The online version contains supplementary material available at 10.1007/s00723-023-01611-1.
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Affiliation(s)
- Valentina Vitali
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex, and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, KY16 9ST Scotland
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
- Department of Chemistry “Ugo Schiff”, University of Florence, Via Della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Katrin Ackermann
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex, and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, KY16 9ST Scotland
| | - Gregor Hagelueken
- Institute of Structural Biology, Biomedical Center, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Bela E. Bode
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex, and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, KY16 9ST Scotland
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