1
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Zuiani A, Dulberger CL, De Silva NS, Marquette M, Lu YJ, Palowitch GM, Dokic A, Sanchez-Velazquez R, Schlatterer K, Sarkar S, Kar S, Chawla B, Galeev A, Lindemann C, Rothenberg DA, Diao H, Walls AC, Addona TA, Mensa F, Vogel AB, Stuart LM, van der Most R, Srouji JR, Türeci Ö, Gaynor RB, Şahin U, Poran A. A multivalent mRNA monkeypox virus vaccine (BNT166) protects mice and macaques from orthopoxvirus disease. Cell 2024; 187:1363-1373.e12. [PMID: 38366591 DOI: 10.1016/j.cell.2024.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/13/2023] [Accepted: 01/12/2024] [Indexed: 02/18/2024]
Abstract
In response to the 2022 outbreak of mpox driven by unprecedented human-to-human monkeypox virus (MPXV) transmission, we designed BNT166, aiming to create a highly immunogenic, safe, accessible, and scalable next-generation vaccine against MPXV and related orthopoxviruses. To address the multiple viral forms and increase the breadth of immune response, two candidate multivalent mRNA vaccines were evaluated pre-clinically: a quadrivalent vaccine (BNT166a; encoding the MPXV antigens A35, B6, M1, H3) and a trivalent vaccine (BNT166c; without H3). Both candidates induced robust T cell responses and IgG antibodies in mice, including neutralizing antibodies to both MPXV and vaccinia virus. In challenge studies, BNT166a and BNT166c provided complete protection from vaccinia, clade I, and clade IIb MPXV. Furthermore, immunization with BNT166a was 100% effective at preventing death and at suppressing lesions in a lethal clade I MPXV challenge in cynomolgus macaques. These findings support the clinical evaluation of BNT166, now underway (NCT05988203).
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Özlem Türeci
- BioNTech SE, Mainz, Germany; HI-TRON - Helmholtz Institute for Translational Oncology Mainz by DKFZ, Mainz, Germany
| | | | - Uğur Şahin
- BioNTech SE, Mainz, Germany; TRON gGmbH - Translational Oncology at the University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
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2
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Arieta CM, Xie YJ, Rothenberg DA, Diao H, Harjanto D, Meda S, Marquart K, Koenitzer B, Sciuto TE, Lobo A, Zuiani A, Krumm SA, Cadima Couto CI, Hein S, Heinen AP, Ziegenhals T, Liu-Lupo Y, Vogel AB, Srouji JR, Fesser S, Thanki K, Walzer K, Addona TA, Türeci Ö, Şahin U, Gaynor RB, Poran A. The T-cell-directed vaccine BNT162b4 encoding conserved non-spike antigens protects animals from severe SARS-CoV-2 infection. Cell 2023; 186:2392-2409.e21. [PMID: 37164012 PMCID: PMC10099181 DOI: 10.1016/j.cell.2023.04.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/12/2023] [Accepted: 04/05/2023] [Indexed: 05/12/2023]
Abstract
T cell responses play an important role in protection against beta-coronavirus infections, including SARS-CoV-2, where they associate with decreased COVID-19 disease severity and duration. To enhance T cell immunity across epitopes infrequently altered in SARS-CoV-2 variants, we designed BNT162b4, an mRNA vaccine component that is intended to be combined with BNT162b2, the spike-protein-encoding vaccine. BNT162b4 encodes variant-conserved, immunogenic segments of the SARS-CoV-2 nucleocapsid, membrane, and ORF1ab proteins, targeting diverse HLA alleles. BNT162b4 elicits polyfunctional CD4+ and CD8+ T cell responses to diverse epitopes in animal models, alone or when co-administered with BNT162b2 while preserving spike-specific immunity. Importantly, we demonstrate that BNT162b4 protects hamsters from severe disease and reduces viral titers following challenge with viral variants. These data suggest that a combination of BNT162b2 and BNT162b4 could reduce COVID-19 disease severity and duration caused by circulating or future variants. BNT162b4 is currently being clinically evaluated in combination with the BA.4/BA.5 Omicron-updated bivalent BNT162b2 (NCT05541861).
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Affiliation(s)
| | - Yushu Joy Xie
- BioNTech US, 40 Erie Street, Cambridge, MA 02139, USA
| | | | - Huitian Diao
- BioNTech US, 40 Erie Street, Cambridge, MA 02139, USA
| | - Dewi Harjanto
- BioNTech US, 40 Erie Street, Cambridge, MA 02139, USA
| | - Shirisha Meda
- BioNTech US, 40 Erie Street, Cambridge, MA 02139, USA
| | | | | | | | | | - Adam Zuiani
- BioNTech US, 40 Erie Street, Cambridge, MA 02139, USA
| | | | | | | | | | | | | | | | - John R Srouji
- BioNTech US, 40 Erie Street, Cambridge, MA 02139, USA
| | | | | | | | | | - Özlem Türeci
- BioNTech SE, An der Goldgrube 12, 55131 Mainz, Germany; HI-TRON - Helmholtz Institute for Translational Oncology Mainz by DKFZ, Obere Zahlbacherstr. 63, 55131 Mainz, Germany
| | - Uğur Şahin
- BioNTech SE, An der Goldgrube 12, 55131 Mainz, Germany; TRON gGmbH - Translational Oncology at the University Medical Center of the Johannes Gutenberg University, Freiligrathstraße 12, 55131 Mainz, Germany
| | | | - Asaf Poran
- BioNTech US, 40 Erie Street, Cambridge, MA 02139, USA.
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3
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Vyasamneni R, Kohler V, Karki B, Mahimkar G, Esaulova E, McGee J, Kallin D, Sheen JH, Harjanto D, Kirsch M, Poran A, Dong J, Srinivasan L, Gaynor RB, Bushway ME, Srouji JR. A universal MHCII technology platform to characterize antigen-specific CD4 + T cells. Cell Rep Methods 2023; 3:100388. [PMID: 36814840 PMCID: PMC9939426 DOI: 10.1016/j.crmeth.2022.100388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 11/08/2022] [Accepted: 12/20/2022] [Indexed: 01/15/2023]
Abstract
CD4+ T cells are critical to the immune system and perform multiple functions; therefore, their identification and characterization are crucial to better understanding the immune system in both health and disease states. However, current methods rarely preserve their ex vivo phenotype, thus limiting our understanding of their in vivo functions. Here we introduce a flexible, rapid, and robust platform for ex vivo CD4+ T cell identification. By combining MHCII allele purification, allele-independent peptide loading, and multiplexed flow cytometry technologies, we can enable high-throughput personalized CD4+ T cell identification, immunophenotyping, and sorting. Using this platform in combination with single-cell sorting and multimodal analyses, we identified and characterized antigen-specific CD4+ T cells relevant to COVID-19 and cancer neoantigen immunotherapy. Overall, our platform can be used to detect and characterize CD4+ T cells across multiple diseases, with potential to guide CD4+ T cell epitope design for any disease-specific immunization strategy.
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Affiliation(s)
| | | | - Binisha Karki
- BioNTech US, Inc., 40 Erie Street, Cambridge, MA 02139, USA
| | - Gauri Mahimkar
- BioNTech US, Inc., 40 Erie Street, Cambridge, MA 02139, USA
| | | | - Jonathan McGee
- BioNTech US, Inc., 40 Erie Street, Cambridge, MA 02139, USA
| | - Daniel Kallin
- BioNTech US, Inc., 40 Erie Street, Cambridge, MA 02139, USA
| | | | - Dewi Harjanto
- BioNTech US, Inc., 40 Erie Street, Cambridge, MA 02139, USA
| | - Miles Kirsch
- BioNTech US, Inc., 40 Erie Street, Cambridge, MA 02139, USA
| | - Asaf Poran
- BioNTech US, Inc., 40 Erie Street, Cambridge, MA 02139, USA
| | - Jesse Dong
- BioNTech US, Inc., 40 Erie Street, Cambridge, MA 02139, USA
| | | | | | | | - John R. Srouji
- BioNTech US, Inc., 40 Erie Street, Cambridge, MA 02139, USA
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4
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Choi J, Goulding SP, Conn BP, McGann CD, Dietze JL, Kohler J, Lenkala D, Boudot A, Rothenberg DA, Turcott PJ, Srouji JR, Foley KC, Rooney MS, van Buuren MM, Gaynor RB, Abelin JG, Addona TA, Juneja VR. Systematic discovery and validation of T cell targets directed against oncogenic KRAS mutations. Cell Rep Methods 2021; 1:100084. [PMID: 35474673 PMCID: PMC9017224 DOI: 10.1016/j.crmeth.2021.100084] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 08/04/2021] [Accepted: 08/20/2021] [Indexed: 12/27/2022]
Abstract
Oncogenic mutations in KRAS can be recognized by T cells on specific class I human leukocyte antigen (HLA-I) molecules, leading to tumor control. To date, the discovery of T cell targets from KRAS mutations has relied on occasional T cell responses in patient samples or the use of transgenic mice. To overcome these limitations, we have developed a systematic target discovery and validation pipeline. We evaluate the presentation of mutant KRAS peptides on individual HLA-I molecules using targeted mass spectrometry and identify 13 unpublished KRASG12C/D/R/V mutation/HLA-I pairs and nine previously described pairs. We assess immunogenicity, generating T cell responses to nearly all targets. Using cytotoxicity assays, we demonstrate that KRAS-specific T cells and T cell receptors specifically recognize endogenous KRAS mutations. The discovery and validation of T cell targets from KRAS mutations demonstrate the potential for this pipeline to aid the development of immunotherapies for important cancer targets.
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Affiliation(s)
- Jaewon Choi
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | - Scott P. Goulding
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | - Brandon P. Conn
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | | | - Jared L. Dietze
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | - Jessica Kohler
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | - Divya Lenkala
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | - Antoine Boudot
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | | | - Paul J. Turcott
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | - John R. Srouji
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | - Kendra C. Foley
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | - Michael S. Rooney
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | | | - Richard B. Gaynor
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | | | - Terri A. Addona
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
| | - Vikram R. Juneja
- BioNTech US Inc., 40 Erie Street, Suite 110, Cambridge, MA 02139, USA
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5
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Srouji JR, Xu A, Park A, Kirsch JF, Brenner SE. The evolution of function within the Nudix homology clan. Proteins 2017; 85:775-811. [PMID: 27936487 PMCID: PMC5389931 DOI: 10.1002/prot.25223] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/15/2016] [Accepted: 11/28/2016] [Indexed: 01/01/2023]
Abstract
The Nudix homology clan encompasses over 80,000 protein domains from all three domains of life, defined by homology to each other. Proteins with a domain from this clan fall into four general functional classes: pyrophosphohydrolases, isopentenyl diphosphate isomerases (IDIs), adenine/guanine mismatch-specific adenine glycosylases (A/G-specific adenine glycosylases), and nonenzymatic activities such as protein/protein interaction and transcriptional regulation. The largest group, pyrophosphohydrolases, encompasses more than 100 distinct hydrolase specificities. To understand the evolution of this vast number of activities, we assembled and analyzed experimental and structural data for 205 Nudix proteins collected from the literature. We corrected erroneous functions or provided more appropriate descriptions for 53 annotations described in the Gene Ontology Annotation database in this family, and propose 275 new experimentally-based annotations. We manually constructed a structure-guided sequence alignment of 78 Nudix proteins. Using the structural alignment as a seed, we then made an alignment of 347 "select" Nudix homology domains, curated from structurally determined, functionally characterized, or phylogenetically important Nudix domains. Based on our review of Nudix pyrophosphohydrolase structures and specificities, we further analyzed a loop region downstream of the Nudix hydrolase motif previously shown to contact the substrate molecule and possess known functional motifs. This loop region provides a potential structural basis for the functional radiation and evolution of substrate specificity within the hydrolase family. Finally, phylogenetic analyses of the 347 select protein domains and of the complete Nudix homology clan revealed general monophyly with regard to function and a few instances of probable homoplasy. Proteins 2017; 85:775-811. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- John R. Srouji
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Present address: Molecular and Cellular Biology DepartmentHarvard UniversityCambridgeMassachusetts02138
| | - Anting Xu
- Graduate Study in Comparative Biochemistry, University of CaliforniaBerkeleyCalifornia94720
| | - Annsea Park
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Jack F. Kirsch
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Study in Comparative Biochemistry, University of CaliforniaBerkeleyCalifornia94720
| | - Steven E. Brenner
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Study in Comparative Biochemistry, University of CaliforniaBerkeleyCalifornia94720
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6
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Nguyen VN, Park A, Xu A, Srouji JR, Brenner SE, Kirsch JF. Substrate specificity characterization for eight putative nudix hydrolases. Evaluation of criteria for substrate identification within the Nudix family. Proteins 2016; 84:1810-1822. [PMID: 27618147 PMCID: PMC5158307 DOI: 10.1002/prot.25163] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 08/30/2016] [Accepted: 09/06/2016] [Indexed: 11/16/2022]
Abstract
The nearly 50,000 known Nudix proteins have a diverse array of functions, of which the most extensively studied is the catalyzed hydrolysis of aberrant nucleotide triphosphates. The functions of 171 Nudix proteins have been characterized to some degree, although physiological relevance of the assayed activities has not always been conclusively demonstrated. We investigated substrate specificity for eight structurally characterized Nudix proteins, whose functions were unknown. These proteins were screened for hydrolase activity against a 74-compound library of known Nudix enzyme substrates. We found substrates for four enzymes with kcat /Km values >10,000 M-1 s-1 : Q92EH0_LISIN of Listeria innocua serovar 6a against ADP-ribose, Q5LBB1_BACFN of Bacillus fragilis against 5-Me-CTP, and Q0TTC5_CLOP1 and Q0TS82_CLOP1 of Clostridium perfringens against 8-oxo-dATP and 3'-dGTP, respectively. To ascertain whether these identified substrates were physiologically relevant, we surveyed all reported Nudix hydrolytic activities against NTPs. Twenty-two Nudix enzymes are reported to have activity against canonical NTPs. With a single exception, we find that the reported kcat /Km values exhibited against these canonical substrates are well under 105 M-1 s-1 . By contrast, several Nudix enzymes show much larger kcat /Km values (in the range of 105 to >107 M-1 s-1 ) against noncanonical NTPs. We therefore conclude that hydrolytic activities exhibited by these enzymes against canonical NTPs are not likely their physiological function, but rather the result of unavoidable collateral damage occasioned by the enzymes' inability to distinguish completely between similar substrate structures. Proteins 2016; 84:1810-1822. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Vi N. Nguyen
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Annsea Park
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Anting Xu
- Graduate Program in Comparative BiochemistryUniversity of CaliforniaBerkeleyCalifornia94720
| | - John R. Srouji
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Present address: Molecular and Cellular Biology DepartmentHarvard UniversityCambridgeMA02138
| | - Steven E. Brenner
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Program in Comparative BiochemistryUniversity of CaliforniaBerkeleyCalifornia94720
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Jack F. Kirsch
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Program in Comparative BiochemistryUniversity of CaliforniaBerkeleyCalifornia94720
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7
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Muratore KE, Engelhardt BE, Srouji JR, Jordan MI, Brenner SE, Kirsch JF. Molecular function prediction for a family exhibiting evolutionary tendencies toward substrate specificity swapping: recurrence of tyrosine aminotransferase activity in the Iα subfamily. Proteins 2013; 81:1593-609. [PMID: 23671031 PMCID: PMC3823064 DOI: 10.1002/prot.24318] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 04/11/2013] [Accepted: 04/19/2013] [Indexed: 11/17/2022]
Abstract
The subfamily Iα aminotransferases are typically categorized as having narrow specificity toward carboxylic amino acids (AATases), or broad specificity that includes aromatic amino acid substrates (TATases). Because of their general role in central metabolism and, more specifically, their association with liver-related diseases in humans, this subfamily is biologically interesting. The substrate specificities for only a few members of this subfamily have been reported, and the reliable prediction of substrate specificity from protein sequence has remained elusive. In this study, a diverse set of aminotransferases was chosen for characterization based on a scoring system that measures the sequence divergence of the active site. The enzymes that were experimentally characterized include both narrow-specificity AATases and broad-specificity TATases, as well as AATases with broader-specificity and TATases with narrower-specificity than the previously known family members. Molecular function and phylogenetic analyses underscored the complexity of this family's evolution as the TATase function does not follow a single evolutionary thread, but rather appears independently multiple times during the evolution of the subfamily. The additional functional characterizations described in this article, alongside a detailed sequence and phylogenetic analysis, provide some novel clues to understanding the evolutionary mechanisms at work in this family.
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Affiliation(s)
- Kathryn E Muratore
- Department of Molecular and Cell Biology, University of California, Berkeley, California
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8
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Engelhardt BE, Jordan MI, Srouji JR, Brenner SE. Genome-scale phylogenetic function annotation of large and diverse protein families. Genome Res 2011; 21:1969-80. [PMID: 21784873 PMCID: PMC3205580 DOI: 10.1101/gr.104687.109] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Accepted: 07/11/2011] [Indexed: 11/25/2022]
Abstract
The Statistical Inference of Function Through Evolutionary Relationships (SIFTER) framework uses a statistical graphical model that applies phylogenetic principles to automate precise protein function prediction. Here we present a revised approach (SIFTER version 2.0) that enables annotations on a genomic scale. SIFTER 2.0 produces equivalently precise predictions compared to the earlier version on a carefully studied family and on a collection of 100 protein families. We have added an approximation method to SIFTER 2.0 and show a 500-fold improvement in speed with minimal impact on prediction results in the functionally diverse sulfotransferase protein family. On the Nudix protein family, previously inaccessible to the SIFTER framework because of the 66 possible molecular functions, SIFTER achieved 47.4% accuracy on experimental data (where BLAST achieved 34.0%). Finally, we used SIFTER to annotate all of the Schizosaccharomyces pombe proteins with experimental functional characterizations, based on annotations from proteins in 46 fungal genomes. SIFTER precisely predicted molecular function for 45.5% of the characterized proteins in this genome, as compared with four current function prediction methods that precisely predicted function for 62.6%, 30.6%, 6.0%, and 5.7% of these proteins. We use both precision-recall curves and ROC analyses to compare these genome-scale predictions across the different methods and to assess performance on different types of applications. SIFTER 2.0 is capable of predicting protein molecular function for large and functionally diverse protein families using an approximate statistical model, enabling phylogenetics-based protein function prediction for genome-wide analyses. The code for SIFTER and protein family data are available at http://sifter.berkeley.edu.
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Affiliation(s)
- Barbara E Engelhardt
- Electrical Engineering and Computer Science Department, University of California, Berkeley, California 94720, USA.
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9
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Aminetzach YT, Srouji JR, Kong CY, Hoekstra HE. Convergent evolution of novel protein function in shrew and lizard venom. Curr Biol 2009; 19:1925-31. [PMID: 19879144 DOI: 10.1016/j.cub.2009.09.022] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 09/08/2009] [Accepted: 09/14/2009] [Indexed: 11/26/2022]
Abstract
How do proteins evolve novel functions? To address this question, we are studying the evolution of a mammalian toxin, the serine protease BLTX [1], from the salivary glands of the North American shrew Blarina brevicauda. Here, we examine the molecular changes responsible for promoting BLTX toxicity. First, we show that regulatory loops surrounding the BLTX active site have evolved adaptively via acquisition of small insertions and subsequent accelerated sequence evolution. Second, these mutations introduce a novel chemical environment into the catalytic cleft of BLTX. Third, molecular-dynamic simulations show that the observed changes create a novel chemical and physical topology consistent with increased enzyme catalysis. Finally, we show that a toxic serine protease from the Mexican beaded lizard (GTX) [2] has evolved convergently through almost identical functional changes. Together, these results suggest that the evolution of toxicity might be predictable-arising via adaptive structural modification of analogous labile regulatory loops of an ancestral serine protease-and thus might aid in the identification of other toxic proteins.
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Affiliation(s)
- Yael T Aminetzach
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
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