Publications by authors named "Abbas Razvi"

Article Synopsis
  • Host cell proteins (HCPs) are impurities from biopharmaceutical production that need to be removed to ensure product safety and quality, as per regulatory requirements.
  • The standard method for detecting HCPs is ELISA, but using liquid chromatography-mass spectrometry (LC-MS) offers more precise identification and quantification of individual HCPs.
  • A novel workflow developed in this article involves using Fc-receptor affinity chromatography for HCP isolation, followed by a single-pot digestion method, which is more effective than traditional techniques for monitoring low-abundant HCPs in therapeutic monoclonal antibodies.
View Article and Find Full Text PDF

Solutions of monoclonal antibodies (mAbs) can show increased viscosity at high concentration, which can be a disadvantage during protein purification, filling, and administration. The viscosity is determined by protein-protein-interactions, which are influenced by the antibody's sequence as well as solution conditions, like pH, buffer type, or the presence of salts and other excipients. To predict viscosity, experimental parameters, like the diffusion interaction parameter (kD), or computational tools harnessing information derived from primary sequence, are often used, but a reliable predictive tool is still missing.

View Article and Find Full Text PDF

Introduction Hepatitis B virus (HBV) is the leading cause of cirrhosis in the developing world. Despite the development of effective vaccine(s) and direct-acting antivirals (DAAs) such as tenofovir and entecavir, the eradication of chronic HBV remains a distant dream in endemic regions. Factors such as treatment naivety, longer duration of disease, late diagnosis, family history of liver disorders and hepatocellular carcinoma, fatty liver disease, multiple comorbidities, alcoholism, use of tobacco products, noncompliance to drugs, and loss to follow-up all contribute to disease progression and development of complications.

View Article and Find Full Text PDF

Introduction Asthma is a clinical syndrome characterized by reversible and recurrent airway obstruction leading to the symptoms of wheezing, cough, shortness of breath, fatigue, and respiratory distress. It is one of the most common lung pathologies worldwide. Its incidence is on the rise in Pakistan, which may be due to overt environmental pollution or improving screening protocols.

View Article and Find Full Text PDF
Article Synopsis
  • Protein folding is central to the proteostasis network, where chaperone proteins interact with other proteins to ensure proper folding, and this interaction impacts cellular functions.
  • The study investigates the effect of the Phe508 deletion in the CFTR protein on its interaction with chaperones, revealing that this mutant form is trapped in an inappropriate folding state, known as a 'chaperone trap.'
  • Correcting the temperature to 30°C helps restore normal function and interaction patterns of the CFTR protein, emphasizing the importance of proper folding pathways in diseases like cystic fibrosis.
View Article and Find Full Text PDF
Article Synopsis
  • Aha1 enhances Hsp90's ATPase activity by binding to its dimer interface, which is crucial for modulating its function and client activity.
  • Mutations in Aha1's domains hinder its binding to Hsp90, impacting ATPase stimulation and the proper functioning of cystic fibrosis-related proteins like CFTR.
  • The study suggests that Aha1 plays a key role in maintaining protein stability by managing the interaction time between Hsp90 and its clients, potentially preventing misfolding and related disorders.
View Article and Find Full Text PDF

Our goal was to gain a better understanding of how protein stability can be increased by improving beta-turns. We studied 22 beta-turns in nine proteins with 66-370 residues by replacing other residues with proline and glycine and measuring the stability. These two residues are statistically preferred in some beta-turn positions.

View Article and Find Full Text PDF

Using cryo-electron microscopy, we have solved the structure of an icosidodecahedral COPII coat involved in cargo export from the endoplasmic reticulum (ER) coassembled from purified cargo adaptor Sec23-24 and Sec13-31 lattice-forming complexes. The coat structure shows a tetrameric assembly of the Sec23-24 adaptor layer that is well positioned beneath the vertices and edges of the Sec13-31 lattice. Fitting the known crystal structures of the COPII proteins into the density map reveals a flexible hinge region stemming from interactions between WD40 beta-propeller domains present in Sec13 and Sec31 at the vertices.

View Article and Find Full Text PDF

Studies that compare proteins from thermophilic and mesophilic organisms can provide insights into ability of thermophiles to function at their high habitat temperatures and may provide clues that enable us to better define the forces that stabilize all proteins. Most of the comparative studies have focused on thermal stability and show, as expected, that thermophilic proteins have higher Tm values than their mesophilic counterparts. Although these comparisons are useful, more detailed thermodynamic analyses are required to reach a more complete understanding of the mechanisms thermophilic protein employ to remain folded over a wider range of temperatures.

View Article and Find Full Text PDF

A thermodynamic stability study of five histidine-containing phosphocarrier protein (HPr) homologues derived from organisms inhabiting diverse environments is described. These HPr homologues are from Bacillus subtilis (Bs), Streptococcus thermophilus (St), Bacillus staerothermophilus (Bst), Bacillus halodurans (Bh), and Oceanobacillus iheyensis (Oi). Analyses of solvent and thermal denaturation experiments provide the cardinal thermodynamic parameters, like deltaG, deltaH, deltaS, T(m), and deltaC(p), that characterize the conformational stability for each homologue.

View Article and Find Full Text PDF
Article Synopsis
  • - The study focuses on the protein HPr from both mesophilic and thermophilic organisms to understand what makes proteins from extreme environments more stable, which could enhance our knowledge of protein folding.
  • - The researchers successfully determined the high-resolution structures of HPr from the thermophile Bacillus stearothermophilus and a variant, revealing a monomeric form and a unique domain-swapped dimer that differs from a similar protein in Bacillus subtilis.
  • - The study also explores the stability of these HPr proteins through thermal and solvent denaturation methods, while analyzing their biochemical and biophysical properties to explain the observed differences in stability.
View Article and Find Full Text PDF