Unusual Self-Assembly of the Recombinant Chlamydia trachomatis Major Outer Membrane Protein-Based Fusion Antigen CTH522 Into Protein Nanoparticles

TY - JOUR

T1 - Unusual Self-Assembly of the Recombinant Chlamydia trachomatis Major Outer Membrane Protein-Based Fusion Antigen CTH522 Into Protein Nanoparticles

AU - Rose, Fabrice

AU - Karlsen, Kasper

AU - Jensen, Pernille Rønde

AU - Jakobsen, Rasmus Uffe

AU - Wood, Grith Krøyer

AU - Rand, Kasper Dyrberg

AU - Godiksen, Helene

AU - Andersen, Peter

AU - Follmann, Frank

AU - Foged, Camilla

N1 - Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

PY - 2018/6

Y1 - 2018/6

N2 - Sexually transmitted Chlamydia trachomatis infects more than 100 million people annually, and untreated chlamydia infections can cause severe complications. Therefore, there is an urgent need for a chlamydia vaccine. The Ctrachomatis major outer membrane protein (MOMP) is highly immunogenic but is a challenging vaccine candidate by being an integral membrane protein, and the immunogenicity depends on a correctly folded structure. We investigated the biophysical properties of the recombinant MOMP-based fusion antigen CTH522, which is tested in early human clinical trials. It consists of a truncated and cysteine-free version of MOMP fused to 4 variable domains from serovars D-G. In the native state, CTH522 did not exist as a monomer but showed an unusual self-assembly into nanoparticles with a negative zeta potential. In contrast to the β-barrel structure of MOMP, native CTH522 contained no well-defined secondary structural elements, and no thermal transitions were measurable. Chemical unfolding resulted in monomers that upon removal of the denaturant self-assembled into higher order structures, comparable to the structure of the native protein. The conformation of CTH522 in nanoparticles is thus not entirely random and contains structural elements stabilized via denaturant-disruptable hydrophobic interactions. In conclusion, CTH522 has an unusual quaternary structure of supramolecular self-assemblies.

AB - Sexually transmitted Chlamydia trachomatis infects more than 100 million people annually, and untreated chlamydia infections can cause severe complications. Therefore, there is an urgent need for a chlamydia vaccine. The Ctrachomatis major outer membrane protein (MOMP) is highly immunogenic but is a challenging vaccine candidate by being an integral membrane protein, and the immunogenicity depends on a correctly folded structure. We investigated the biophysical properties of the recombinant MOMP-based fusion antigen CTH522, which is tested in early human clinical trials. It consists of a truncated and cysteine-free version of MOMP fused to 4 variable domains from serovars D-G. In the native state, CTH522 did not exist as a monomer but showed an unusual self-assembly into nanoparticles with a negative zeta potential. In contrast to the β-barrel structure of MOMP, native CTH522 contained no well-defined secondary structural elements, and no thermal transitions were measurable. Chemical unfolding resulted in monomers that upon removal of the denaturant self-assembled into higher order structures, comparable to the structure of the native protein. The conformation of CTH522 in nanoparticles is thus not entirely random and contains structural elements stabilized via denaturant-disruptable hydrophobic interactions. In conclusion, CTH522 has an unusual quaternary structure of supramolecular self-assemblies.

U2 - 10.1016/j.xphs.2018.02.005

DO - 10.1016/j.xphs.2018.02.005

M3 - Journal article

C2 - 29452143

SN - 0022-3549

VL - 107

SP - 1690

EP - 1700

JO - Journal of Pharmaceutical Sciences

JF - Journal of Pharmaceutical Sciences

IS - 6

ER -