Current Protein and Peptide Science - Volume 24, Issue 1, 2023

In 2007, diabetes affected around 244 million people across the globe. The number of diabetics worldwide is projected to reach 370 million by 2030. With diabetes incidence reaching epidemic proportions globally, diabetic nephropathy (DN) has emerged as one of the most difficult health conditions. Although therapeutic approaches such as rigorous blood glucose and blood pressure management are successful in preventing DN, they are far from ideal, and the number of diabetic patients with endstage renal disease continues to grow. As a result, a unique treatment approach for DN should be devised. There is mounting evidence that advanced glycation end products (AGEs), senescent macro protein derivatives generated at an accelerated pace in DN, contribute to DN by generating oxidative stress. The purpose of this article is to discuss the pathophysiological significance of AGEs and their receptor in DN.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitously present in the environment. These compounds have demonstrated both mutagenic and carcinogenic properties. In the past few decades, scientists have constantly been looking for a possible route to their biological degradation. Bacterial ring hydroxylating dioxygenases (RHDs) implicated in the polycyclic aromatic hydrocarbon degradation comprise a large family of enzymes. RHD catalyzes the stereospecific oxidation of PAHs by incorporating molecular oxygen into inert aromatic nuclei. These biocatalysts hold the potential to completely transform and mineralize toxic forms of these compounds into non-toxic forms. RHDsmediated oxygenation produces cis-dihydrodiols, a chiral compound used in pharmaceutical industries. The Molecular investigation of 16S rRNA and key functional genes involved in pollutant degradation have revealed the dominant occurrence of phylum proteobacteria and actinobacteria in hydrocarbonpolluted environments. The present review is aimed at narrating the diversity, distribution, structural and functional characteristics of RHDs. The review further highlights key amino acids participating in RHDs catalysis. It also discusses the robustness of protein engineering methods in improving the structural and functional activity of the ring hydroxylating dioxygenases.

ASXL2, as a transcription regulator, is a research hotspot for tumor detection. The aberrant expression of ASXL2 protein has been mainly implicated in malignant hematological and heart diseases. To further explore the predictive value of ASXL2 in diseases, we reviewed the structure and function of ASXL2 protein, the post-translational modification mechanism, and the expression of ASXL2 protein in the pathogenesis of different diseases to provide a theoretical basis and support for the development of future treatments.

Platelets and their progenitors express high levels of integrin αIIbβ3, which plays a key role in platelet functions, hemostasis, and arterial thrombosis. Because of their quick and high efficacy, the three anti-αIIbβ3 drugs, abciximab, eptifibatide, and tirofiban, are regarded as potent anti-thrombotics and clinically approved by US Food and Drug Administration. However, because they interfere with the inside-out signaling of αIIbβ3, which is required for stable platelet adhesion and aggregation, the application of abciximab, eptifibatide, and tirofiban is restricted to patients undergoing percutaneous coronary intervention. On the other hand, the outside-in signaling of αIIbβ3 in platelets appears to be responsible for thrombus stabilization, and selective interference with the propagation of outside-in signals might signify a new therapeutic strategy to preferentially inhibit platelet-rich arterial thrombosis with less bleeding issues caused by way of compromised major hemostasis. The purpose of this review is to describe the bidirectional signal transduction of integrin αIIbβ3 in platelets with a focus on outside-in signaling, more efficient and safer anti-αIIbβ3 peptides, and the potential drug targets for future anti-platelet research.

Sodium, potassium, and protons are the most important ions for life on earth, and their homeostasis is crucially needed for the survival of cells. The biological cells have developed a system that regulates and maintains the integrity of the cells by facilitating the exchange of these ions. These systems include the specific type of ion transporter membrane proteins such as cation-proton antiporters. Cation proton antiporters induce the active transport of cations like Na+, K+ or Ca+ across the cell membrane in exchange for protons (H+) and make the organism able to survive in alkaline conditions, high or fluctuating pH, stressed temperature or osmolarity. The secondary transporter proteins exploit the properties of various specific structural components to carry out efficient active transport. Ec-NhaA crystal structure was resolved at acidic pH at which the protein is downregulated, which discloses the presence of 12 transmembrane (TM) helices. This structural fold, the “NhaA fold,” is speculated to contribute to the cation-binding site and conformational alterations during transport in various antiporters. Irrespective of the variation in the composition of amino acids and lengths of proteins, several other members of the CPA family, such as NmABST, PaNhaP, and MjNhaP1, share the common structural features of the Ec-NhaA. The present review elucidates the existence of CPAs throughout all the kingdoms and the structural intercorrelation with their function. The interplay in the structurefunction of membrane transporter protein may be implemented to explore the plethora of biological events such as conformation, folding, ion binding and translocation etc.

With 1.5 million new infections and 690,000 AIDS-related deaths globally each year, HIV- 1 remains a pathogen of significant public health concern. Although a wide array of effective antiretroviral drugs have been discovered, these largely target intracellular stages of the viral infectious cycle, and inhibitors that act at or before the point of viral entry still require further advancement. A unique class of HIV-1 entry inhibitors, called peptide triazoles (PTs), has been developed, which irreversibly inactivates Env trimers by exploiting the protein structure’s innate metastable nature. PTs, and a related group of inhibitors called peptide triazole thiols (PTTs), are peptide compounds that dually engage the CD4 receptor and coreceptor binding sites of Env’s gp120 subunit. This triggers dramatic conformational rearrangements of Env, including the shedding of gp120 (PTs and PTTs) and lytic transformation of the gp41 subunit to a post-fusion-like arrangement (PTTs). Due to the nature of their dual receptor site engagement, PT/PTT-induced conformational changes may elucidate mechanisms behind the native fusion program of Env trimers following receptor and coreceptor engagement, including the role of thiols in fusion. In addition to inactivating Env, PTT-induced structural transformation enhances the exposure of important and conserved neutralizable regions of gp41, such as the membrane proximal external region (MPER). PTT-transformed Env could present an intriguing potential vaccine immunogen prototype. In this review, we discuss the origins of the PT class of peptide inhibitors, our current understanding of PT/PTT-induced structural perturbations and viral inhibition, and prospects for using these antagonists for investigating Env structural mechanisms and for vaccine development.

Thymosin β4 (Tβ4) is the β-thymosin (Tβs) with the highest expression level in human cells; it makes up roughly 70-80% of all Tβs in the human body. Combining the mechanism and activity studies of Tβ4 in recent years, we provide an overview of the subtle molecular mechanism, pharmacological action, and clinical applications of Tβ4. As a G-actin isolator, Tβ4 inhibits the polymerization of G-actin by binding to the matching site of G-actin in a 1:1 ratio through conformational and spatial effects. Tβ4 can control the threshold concentration of G-actin in the cytoplasm, influence the balance of depolymerization and polymerization of F-actin (also called Tread Milling of F-actin), and subsequently affect cell's various physiological activities, especially motility, development and differentiation. Based on this, Tβ4 is known to have a wide range of effects, including regulation of inflammation and tumor metastasis, promotion of angiogenesis, wound healing, regeneration of hair follicles, promotion of the development of the nervous system, and improving bone formation and tooth growth. Tβ4 therefore has extensive medicinal applications in many fields, and serves to preserve the kidney, liver, heart, brain, intestine, and other organs, as well as hair loss, skin trauma, cornea repairing, and other conditions. In this review, we focus on the mechanism of action and clinical application of Tβ4 for its main biological functions.

The new coronavirus currently named SARS-CoV-2 was announced by the World Health Organization as the virus causing the COVID-19 pandemic. The pathogenesis of SARS-CoV-2 initiates upon contact of a structural spike protein with the angiotensin II-converting enzyme receptor, leading to the induction of inflammatory mechanisms and progression to severe disease in some cases. Currently, studies have emerged linking COVID-19 with angiotensin-(1-7), demonstrating the potential of angiotensin-(1-7)/Mas Receptor axis induction to control disease severity due to its antiinflammatory, vasodilator, antioxidant, antiproliferative, anticoagulant, antiangiogenic and fibrosis inhibitory effects. The renin angiotensin-system peptide Angiotensin-(1-7) shows a high therapeutic potential for COVID-19 mainly because of its ability to counteract the adverse effects caused in various organs due to angiotensin II-converting enzyme blockade. In light of these factors, the use of convalescent plasma conjugated therapy and Ang (1-7) agonists for the treatment of COVID-19 patients could be recommended. The differential expression of ACE2 and the varied response to SARSCoV- 2 are thought to be connected. According to several investigations, ACE2 antibodies and pharmacological inhibitors might be used to prevent viral entry. Given its capacity to eliminate the virus while ensuring lung and cardiovascular protection by regulating the inflammatory response, angiotensin-( 1-7) is expected to be a safe choice. However, more clinical evidence is required to clarify the therapeutic usage of this peptide. The aim of this review article is to present an update of scientific data and clinical trials on the therapeutic potential of angiotensin-(1-7) in patients with COVID-19.

Globally Ambrosia species (Asteraceae), commonly called ragweed, are recognized to be one of the most problematic groups of invasive weeds and one of the main allergenic genus. Climate and land-use change and air pollution are expected to promote ragweed spread, increase airborne ragweed pollen concentrations (the source of allergens), extend the pollen season, and promote longdistance transport of pollen or sub-pollen particles containing allergens. The allergenicity of pollen itself is going to increase. Likely, all these factors will have meaningful effects in the exacerbation of the sensitization to ragweed pollen and the severity of allergy symptoms. Globally the major health concern regards A. artemisiifolia, because of its very wide global distribution and highly invasive behavior. Together with A. artemisiifolia, also A. trifida and A. psilostachya are species of health concern distributed across different continents, widespread and invasive in several regions. The present review summarizes the characteristics of these species and gives an overview of factors contributing to their allergenicity.