Biology subjects

Jacobs, T. M.

Publications and source records attributed to Jacobs, T. M..

3 recordsLinked to original sources

bioRxiv2022

AlphaFold accurately predicts distinct conformations based on oligomeric state of a de novo designed protein

Using the molecular modeling program Rosetta, we designed a de novo protein, called SEWN0.1, that binds the heterotrimeric G protein Gq. The design is helical, well-folded, and primarily monomeric in solution at a concentration of 10 uM. However, when we solved the crystal structure of SEWN0.1, we observed a dimer in a conformation incompatible with binding Gq. Unintentionally, we had designed a protein that adopts alternate conformations depending on its oligomeric state. Recently, there has been tremendous progress in the field of protein structure prediction as new methods in artificial intelligence have been used to predict structures with high accuracy. We were curious if the structure prediction method AlphaFold could predict the structure of SEWN0.1 and if the prediction depended on oligomeric state. When AlphaFold was used to predict the structure of monomeric SEWN0.1, it produced a model that resembles the Rosetta design model and is compatible with binding Gq, but when used to predict the structure of a dimer, it predicted a conformation that closely resembles the SEWN0.1 crystal structure. AlphaFolds ability to predict multiple conformations for a single protein sequence should be useful for engineering protein switches.

biophysics↗

bioRxiv2020

Engineering Highly Homogenous Tetravalent IgGs with Enhanced Sperm Agglutination Potency

Millions of women avoid using available contraceptives and risk unintended pregnancies every year, due to perceived and/or real side-effects associated with the use of exogenous hormones. Naturally occurring anti-sperm antibodies can prevent fertilization in immune infertile women by limiting sperm permeation through mucus, particularly multivalent antibodies such as sIgA that offers robust agglutination potencies. Unfortunately, sIgA remains challenging to produce in large quantities and easily aggregates. Here, we designed two tetravalent anti-sperm IgGs with a Fab domain previously isolated from an immune infertile woman. Both constructs possess at least 4-fold greater agglutination potency and induced much more rapid sperm agglutination than the parent IgG while exhibiting comparable production yields and identical thermostability as the parent IgG. These tetravalent IgGs offer promise for non-hormonal contraception and underscore the multimerization of IgG as a promising strategy to improve existing mAb therapeutics.

molecular biology↗

bioRxiv2020

Engineering highly multivalent sperm-binding IgG antibodies for potent non-hormonal female contraception

Many women risk unintended pregnancy due to dissatisfaction with available hormonal contraceptive methods. This led us to pursue topical sperm-binding monoclonal antibodies as a strategy for safe, non-hormonal contraception. Motivated by the greater agglutination potencies of polymeric immunoglobulins such as IgM and the exceptional bioprocessing ease in manufacturing IgG, we engineered IgGs possessing 6-10 Fabs against a unique surface antigen universally present on human sperm. These highly multivalent IgGs (HM-IgGs) are at least 10- to 16-fold more potent and faster than the parent IgG at agglutinating sperm, while preserving Fc-mediated trapping of individual spermatozoa in mucus. The increased potencies translate to effective (>99.9%) reduction of progressively motile sperm in the sheep vagina using 33 micrograms of the 10 Fab HM-IgG. HM-IgGs produce at comparable yields and possess identical thermal stability to the parent IgG, with greater homogeneity. HM-IgGs represent not only promising biologics for non-hormonal contraception but also a promising platform for generating potent agglutinating mAb for diverse medical applications.

molecular biology↗