Role of Phage Capsid in the Resistance to UV-C Radiations

Abstract

The conformational variation of the viral capsid structure plays an essential role both for the environmental resistance and acid nuclear release during cellular infection. The aim of this study was to evaluate how capsid rearrangement in engineered phages of M13 protects viral DNA and peptide bonds from damage induced by UV-C radiation. From in silico 3D modelling analysis, two M13 engineered phage clones, namely P9b and 12III1, were chosen for (i) chemical features of amino acids sequences, (ii) rearrangements in the secondary structure of their pVIII proteins and (iii) in turn the interactions involved in phage capsid. Then, their resistance to UV-C radiation and hydrogen peroxide (H2O2) was compared to M13 wild-type vector (pC89) without peptide insert. Results showed that both the phage clones acquired an advantage against direct radiation damage, due to a reorganization of interactions in the capsid for an increase of H-bond and steric interactions. However, only P9b had an increase in resistance against H2O2. These results could help to understand the molecular mechanisms involved in the stability of new virus variants, also providing quick and necessary information to develop effective protocols in the virus inactivation for human activities, such as safety foods and animal-derived materials.

Incidence of Phage Capsid Organization on the Resistance to High Energy Proton Beams

“…Differently to P9b, 12III1 foreign peptide, composed by aromatic and other amino acids favorable to carbonylation, could be subjected to a high degree of oxidative modifications and, consequently, a fragmentation of the protein backbone. These findings are in accordance with our previous results, obtained by treating the same phages with H 2 O 2 [26]. In fact, in these experimental conditions, only P9b showed an increased resistance to induced stress, while no significant difference was recorded between 12III1 and pC89.…”

“…The different behaviours of the three phages exposed to the proton beam could be correlated with a different degree of interaction between pVIII-pVIII proteins, due to the peptides exposed in their N-terminus. In a previous work, we observed that the presence of a foreign amino acid sequence on the capsid protein pVIII of P9b and 12III1 phage clones generated an increase in H-bonds and steric interactions in capsid proteins, resulting in the increased resistance to UV-C radiation damage [26].…”

“…The capsid structure has been suggested to be responsible for the great resistance of M13 to various physical and chemical stresses [20,24,25]. Moreover, we recently reported that the addition of foreign peptides in M13-engineered phages modified the spatial distribution of surface charges and the stretching of the entire capsid, affecting their resistance against UV-C exposure and H 2 O 2 treatment [26,27].…”

Bacteriophage as a potential therapy to control antibiotic-resistant Pseudomonas aeruginosa infection through topical application onto a full-thickness wound in a rat model

“…In addition, it showed good stability at a wide range of temperatures (37,50,60, and 70 °C) and a wide range of pH values (4)(5)(6)(7)(8)(9)(10). According to De Plano et al, the capsid structure of phages has been proposed for their resistance to harsh physical and chemical conditions, including pH and heat [79]. Besides, the reduction in phage titer at harsh pH conditions is due to the aggregation of viral particles, as shown by Langlet et al [80].…”

Genomic characterization of a new phage BUCT541 against Klebsiella pneumoniae K1-ST23 and efficacy assessment in mouse and Galleria mellonella larvae

“…ORF39, ORF52, and ORF53 are annotated as minor capsid protein, coat protein, and capsid stabilizing protein, respectively. The main function of capsid proteins is to protect the stability of DNA (Plano et al, 2021). Because capsid protein sequences are highly conserved, they have been used as a basis for studies into the evolutionary history of phages (Buttimer et al, 2018;Shi et al, 2020).…”