HIV-1 protease is essential for the production of mature, infectious virions and is a major target in antiretroviral therapy. We successfully purified a HIV-1 subtype C variant, L38↑N↑L, containing an insertion of asparagine and leucine at position 38 without the four background mutations - K20R, E35D, R57K, V82I using a modified purification protocol. Isothermal titration calorimetry indicated that 50% of the variant protease sample was in the active conformation compared to 62% of the wild type protease. The secondary structure composition of the variant protease was unaffected by the double insertion. The specific activity and k values of the variant protease were approximately 50% lower than the wild type protease values. The variant protease also exhibited a 1.6-fold increase in k/K when compared to the wild type protease. Differential scanning calorimetry showed a 5 °C increase in T of the variant protease, indicating the variant was more stable than the wild type. Molecular dynamics simulations indicated the variant was more stable and compact than the wild type protease. A 3-4% increase in the flexibility of the hinge regions of the variant protease was observed. In addition, increased flexibility of the flaps, cantilever and fulcrum regions of the variant protease B chain was observed. The variant protease sampled only the closed flap conformation indicating a potential mechanism for drug resistance. The present study highlights the direct impact of a double amino acid insertion in hinge region on enzyme kinetics, conformational stability and dynamics of an HIV-1 subtype C variant protease.
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http://dx.doi.org/10.1007/s10930-023-10132-6 | DOI Listing |
Clin Genet
January 2025
Prenatal Diagnosis and Fetal Medicine Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt.
SUMOylation involves covalent attachment of small ubiquitin-like modifier (SUMO) proteins to specific lysine residues on target proteins and regulates various aspects of their function. Sentrin-specific proteases (SENPs) are key players in both the conjugation reaction of SUMO proteins to their targets and the subsequent deconjugation of SUMO-conjugated substrates. Here, we provide the first comprehensive prenatal description of a lethal syndrome linked to a novel homozygous stop-gain variant in SENP7 c.
View Article and Find Full Text PDFJ Med Virol
January 2025
Institute of Virology, Technical University of Munich/Helmholtz Munich, Munich, Germany.
Hum Cell
January 2025
Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, 310052, China.
This research delves into Primary Hyperoxaluria Type 2 (PH2), an autosomal recessive disorder precipitated by a unique case of compound heterozygous deleterious mutations in the GRHPR gene, specifically the intron2/3 c.214-2 T > G and the exon8 c.864-865delTG, leading to a premature stop codon at p.
View Article and Find Full Text PDFPLoS One
January 2025
Immunology and Immunotherapy Division, Center of Molecular Immunology (CIM), Havana, Cuba.
SARS-CoV-2 has continued spreading around the world in recent years since the initial outbreak in 2019, frequently developing into new variants with greater human infectious capacity. SARS-CoV-2 and its mutants use the angiotensin-converting enzyme 2 (ACE2) as a cellular entry receptor, which has triggered several therapeutic strategies against COVID-19 relying on the use of ACE2 recombinant proteins as decoy receptors. In this work, we propose an ACE2 silent Fc fusion protein (ACE2-hFcLALA) as a candidate therapy against COVID-19.
View Article and Find Full Text PDFJ Dermatol
January 2025
Division of Dermatology, Department of Internal Related, Kobe University Graduate School of Medicine, Kobe, Japan.
Nagashima-type palmoplantar keratosis (NPPK) has been shown to represent a form of autosomal recessive palmoplantar keratosis due to biallelic pathological variants of SERPINB7, which encodes a serine protease inhibitor expressed in the epidermis. Approximately 10 years have elapsed since NPPK was demonstrated to be an independent genetic disease, and the most prevalent palmoplantar keratoderma (PPK) in East Asian countries due to a high prevalence of founder mutations in SERPINB7. Since then, it has become evident that biallelic pathological variants of SERPINA12, which encodes a serine protease inhibitor expressed in the epidermis, can also manifest symptoms analogous to those of NPPK.
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