About the Authors

David C. Pryde

Affiliation Pfizer Worldwide Medicinal Chemistry, Cambridge, United Kingdom

Lyn H. Jones

Affiliation Pfizer Worldwide Medicinal Chemistry, BioTherapeutics Chemistry, Cambridge, Massachusetts, United States of America

David P. Gervais

Current address: Health Protection Agency, Process and Analytical Development Group, Porton Down, Salisbury, United Kingdom

Affiliation Pfizer Vaccine Research, La Jolla, California, United States of America

David R. Stead

Affiliation Pfizer Vaccine Research, La Jolla, California, United States of America

David C. Blakemore

Affiliation Pfizer Worldwide Medicinal Chemistry, Cambridge, United Kingdom

Matthew D. Selby

Current address: UCB Celltech, Slough, Berkshire, United Kingdom

Affiliation Pfizer Worldwide Medicinal Chemistry, BioTherapeutics Chemistry, Cambridge, Massachusetts, United States of America

Alan D. Brown

Affiliation Pfizer Worldwide Medicinal Chemistry, Cambridge, United Kingdom

Jotham W. Coe

Affiliation Pfizer Worldwide Medicinal Chemistry, Groton, Connecticut, United States of America

Matthew Badland

Affiliation Pfizer Chemical Research and Development, Sandwich, United Kingdom

David M. Beal

Current address: School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom

Affiliation Pfizer Worldwide Medicinal Chemistry, BioTherapeutics Chemistry, Cambridge, Massachusetts, United States of America

Rebecca Glen

Affiliation Peakdale Molecular Ltd, Chapel-en-le-Frith, United Kingdom

Yvonne Wharton

Current address: C-Tech Innovation Ltd, Chester, United Kingdom

Affiliation Peakdale Molecular Ltd, Chapel-en-le-Frith, United Kingdom

Gavin J. Miller

Current address: School of Chemistry, the University of Manchester, Manchester, United Kingdom

Affiliation Peakdale Molecular Ltd, Chapel-en-le-Frith, United Kingdom

Phil White

Affiliation Pfizer Vaccine Research, La Jolla, California, United States of America

Ningli Zhang

Affiliation Pfizer Vaccine Research, Ottawa, Ontario, Canada

Michelle Benoit

Affiliation Pfizer Vaccine Research, Ottawa, Ontario, Canada

Karen Robertson

Affiliation Pfizer Vaccine Research, Ottawa, Ontario, Canada

James R. Merson

Affiliation Pfizer Vaccine Research, La Jolla, California, United States of America

Heather L. Davis

Affiliation Pfizer Vaccine Research, Ottawa, Ontario, Canada

Michael J. McCluskie

michael.mccluskie@pfizer.com

Affiliation Pfizer Vaccine Research, Ottawa, Ontario, Canada

Competing Interests

All authors were either under paid employment or consultancy agreement with Pfizer at the time of these studies. Co-authors YW, GM, and RG were employed by Peakdale Molecular Ltd at the time of these studies. Pfizer is pursuing patents and product development on compounds that are mentioned in this paper. There are no marketed products to declare. DP, LJ, DG, DS, D. Blakemore, MS, AB, JC, M. Badland, D. Beal, PW, NZ, M. Benoit, KR, JM, HD and MM all hold shares or share options of Pfizer. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

Author Contributions

Conceived and designed the experiments: DP LJ DG DS D. Blakemore MS AB JC M. Badland D. Beal RG YW GM PW NZ M. Benoit KR JM HD MM. Performed the experiments: DP LJ DG DS D. Blakemore MS M. Badland D. Beal RG YW GM NZ M. Benoit KR. Analyzed the data: DP LJ DG DS D. Blakemore MS M. Badland D. Beal PW NZ M. Benoit KR JM HD MM. Contributed reagents/materials/analysis tools: DP LJ DG DS D. Blakemore MS M. Badland D. Beal RG YW GM NZ M. Benoit KR. Wrote the manuscript: DP LJ DG DS D. Blakemore MS AB JC M. Badland D. Beal RG YW GM PW NZ M. Benoit KR JM HD MM.