China
Africa
Explore chapters and articles related to this topic
Molecular Biology and Gene Therapy
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
Transcription is the intra-nuclear process driven by the RNA polymerase whereby one DNA strand acts as a template for the synthesis of an RNA strand (uracil replaces thymine in RNA). This primary RNA transcript then undergoes post-transcriptional processing, or splicing. The mature mRNA migrates into the cytoplasm where it acts as a template for the synthesis of a polypeptide during translation, via ribosomes. Successive amino acids are added creating a polypeptide chain from to the triplet code on the mRNA, resulting in protein synthesis.
Macronutrients
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Proteins are polymers of different amino acids linked together by peptide bonds in the form of long filaments (polypeptide chains). They wrap themselves in a virtually infinite number of spherical or helical forms, which explains the wide variety of functions performed by proteins (36–38, 47). Proteins differ widely in amino acid content. Some amino acids which are in abundance in one protein may be in meagre amounts in others, and may even be lacking in the rest. Tryptophan, for instance, lacks in certain proteins. However, most of the proteins in animal and plant foods contain all the 20 amino acids (36, 38, 47). The proportion of these amino acids varies as a characteristic of a given protein, but all food proteins contain some of each. Collagen, a fibrillar protein that acts like glue between cells, consists of more than one thousand amino acids. Titin or connectin is a giant protein, greater than one µm in length, the largest known protein. It accounts for the passive elasticity of muscles, and consists of more than 25,000 amino acids (1). Titin is known as the largest sarcomeric protein that resides within the heart muscle. Mutations in the titin gene can cause cardiomyopathies, in particular, dilated cardiomyopathy (48). This cardiac disease is characterized by systolic dysfunction and dilation of the left ventricle (48).
Sickle cell disease
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Marc R. Parrish, John C. Morrison
Hemoglobinopathies complicating pregnancy number in the hundreds, but fortunately most of them are very rare (1). These inherited disorders usually result from structural abnormalities such as additions, deletions, or substitutions in the amino acids that comprise the two pairs of polypeptide chains common to each hemoglobin molecule (Table 1). These amino acid linkages contain either 141 or 147 amino acids, are responsible for the nomenclature, and comprise the common types of hemoglobin such as A, A2, F, and so on (2).
Ribosomopathies and cancer: pharmacological implications
Published in Expert Review of Clinical Pharmacology, 2022
Gazmend Temaj, Sarmistha Saha, Shpend Dragusha, Valon Ejupi, Brigitta Buttari, Elisabetta Profumo, Lule Beqa, Luciano Saso
Ribosomes are ribonucleoprotein complexes discovered by Palade and Porter in 1954 as small round bodies associated with the endoplasmic reticulum (ER), as observed using an electronic microscope [1]. It is well known that genetic information is stored in deoxyribonucleic acid (DNA) molecules, and by the highly regulated mechanism of transcription, genes, as particular segments of DNA, are copied into mRNA (ribonucleic acid) by the RNA polymerase enzyme. Ribosome macromolecules catalyze the translation of information from mRNAs into functional polypeptide chains. Ribosomes consist of large and small subunits. Eukaryotic ribosome consists of a smaller 40S subunit and a large 60S subunit. The smaller 40S subunit consists of 18S ribosomal RNA (rRNA) and 33 ribosomal protein small (RPS) subunits, whereas the 60S subunit contains 28S, 5S, and 5.8S rRNA and 47 ribosomal protein large (RPL) [2,3].
Recent advances in proteolytic stability for peptide, protein, and antibody drug discovery
Published in Expert Opinion on Drug Discovery, 2021
Xianyin Lai, Jason Tang, Mohamed E.H. ElSayed
In addition to the 20 proteinogenic amino acids, more than 800 natural amino acids are known in the literature, while thousands of synthetic amino acids have been reported [98]. The incorporation of non-proteinogenic amino acids that are not found in natural polypeptide chains into a peptide sequence likely will increase the metabolic stability of an analog because the new groups cannot be recognized by the same enzymes. The approach has been applied to many peptide drugs which are on the market [99]. Non-proteinogenic amino acids can be classified into many categories with various terms based on chirality (L vs. D), specific atoms introduced (such as F, S), specific groups introduced (such as CH3), the backbone length (α- vs. β-amino acids), and their combinations. In this section, the most commonly used non-proteinogenic amino acids are discussed as examples.
Antimicrobial peptides and other peptide-like therapeutics as promising candidates to combat SARS-CoV-2
Published in Expert Review of Anti-infective Therapy, 2021
Masoumeh Sadat Mousavi Maleki, Mosayeb Rostamian, Hamid Madanchi
Transferrins are iron-binding proteins with antiviral activity. The most well-known transferrin is lactoferrin (LF), which is a multifunctional 80-kDa glycoprotein and is widely available in various secretory fluids. LF, first discovered in cow’s milk, is evolutionarily highly conserved and is found in humans, mice, and pigs. Its structure consists of a polypeptide chain that has a positively charged N-terminal region. The LF chain has two circular loops connected to three spiral α-helixes, each of which has an iron-binding site. There is a strong connection between two loops when iron binds (the holo-form), which makes LF resistant to proteolysis [40]. Reports have indicated that bovine lactoferrin is a potent inhibitor of a broad number of viruses and has higher antiviral effects than human lactoferrin. Lactoferrin specifically binds to the subunit A2 of the hemagglutinin and inhibits influenza virus infection and related hemagglutination [63]. Lactoferrin has been shown to inhibit infection by binding to adenovirus III and IIIa structural polypeptides targets [64]. The inhibitory effect of LF on DENV [65], Marek’s Disease Virus (MDV) [66], and HCV [67] has been investigated. Recent studies showed that LF can interfere with some of the receptors involved in SARS-CoV-2 pathogenesis and also prevents the entering of the virus via ACE2 to host cells [68]. Therefore, LF may contribute to the prevention and treatment of COVID-19 [68].