Immunofocusing on the conserved fusion peptide of HIV envelope glycoprotein in rhesus macaques.

During infection, the fusion peptide (FP) of HIV envelope glycoprotein (Env) serves a central role in viral fusion with the host cell. As such, the FP is highly conserved and therefore an attractive epitope for vaccine design. Here, we describe a vaccination study in non-human primates (NHPs) where glycan deletions were made on soluble HIV Env to increase FP epitope exposure.

Heterologous prime-boost vaccination drives early maturation of HIV broadly neutralizing antibody precursors in humanized mice.

A protective HIV vaccine will likely need to induce broadly neutralizing antibodies (bnAbs). Vaccination with the germline-targeting immunogen eOD-GT8 60mer adjuvanted with AS01 was found to induce VRC01-class bnAb precursors in 97% of vaccine recipients in the IAVI G001 phase 1 clinical trial; however, heterologous boost immunizations with antigens more similar to the native glycoprotein will be required to induce bnAbs. Therefore, we designed core-g28v2 60mer, a nanoparticle immunogen to be used as a first boost after eOD-GT8 60mer priming.

The Glycan Hole Area of HIV-1 Envelope Trimers Contributes Prominently to the Induction of Autologous Neutralization.

The human immunodeficiency virus type 1 (HIV-1) trimeric envelope glycoprotein (Env) is heavily glycosylated, creating a dense glycan shield that protects the underlying peptidic surface from antibody recognition. The absence of conserved glycans, due to missing potential N-linked glycosylation sites (PNGS), can result in strain-specific, autologous neutralizing antibody (NAb) responses. Here, we sought to gain a deeper understanding of the autologous neutralization by introducing holes in the otherwise dense glycan shields of the AMC011 and AMC016 SOSIP trimers.

Identification, heterologous production and bioactivity of lentinulin A and dendrothelin A, two natural variants of backbone N-methylated peptide macrocycle omphalotin A.

Backbone N-methylation and macrocyclization improve the pharmacological properties of peptides by enhancing their proteolytic stability, membrane permeability and target selectivity. Borosins are backbone N-methylated peptide macrocycles derived from a precursor protein which contains a peptide α-N-methyltransferase domain autocatalytically modifying the core peptide located at its C-terminus. Founding members of borosins are the omphalotins from the mushroom Omphalotus olearius (omphalotins A-I) with nine out of 12 L-amino acids being backbone N-methylated.

Systematic Engineering of a Protein Nanocage for High-Yield, Site-Specific Modification.

Site-specific protein modification is a widely used strategy to attach drugs, imaging agents, or other useful small molecules to protein carriers. N-terminal modification is particularly useful as a high-yielding, site-selective modification strategy that can be compatible with a wide array of proteins. However, this modification strategy is incompatible with proteins with buried or sterically hindered N termini, such as virus-like particles (VLPs) composed of the well-studied MS2 bacteriophage coat protein.

Enzymatic Modification of N-Terminal Proline Residues Using Phenol Derivatives.

A convenient enzymatic strategy is reported for the modification of proline residues in the N-terminal positions of proteins. Using a tyrosinase enzyme isolated from Agaricus bisporus (abTYR), phenols and catechols are oxidized to highly reactive o-quinone intermediates that then couple to N-terminal proline residues in high yield. Key advantages of this bioconjugation method include (1) the use of air-stable precursors that can be prepared on large scale if needed, (2) mild reaction conditions, including low temperatures, (3) the targeting of native functional groups that can be introduced readily on most proteins, and (4) the use of molecular oxygen as the sole oxidant.

Substrate Sorting by a Supercharged Nanoreactor.

Compartmentalization of proteases enables spatially and temporally controlled protein degradation in cells. Here we show that an engineered lumazine synthase protein cage, which possesses a negatively supercharged lumen, can exploit electrostatic effects to sort substrates for an encapsulated protease. This proteasome-like nanoreactor preferentially cleaves positively charged polypeptides over both anionic and zwitterionic substrates, inverting the inherent substrate specificity of the guest enzyme approximately 480 fold.