Proteins are fundamental components of all living cells that participate in some of the most important biological processes, including cell growth and maintenance, movement and defense. They are complex molecules that consist of one or more chains of amino-acids, have distinct three-dimensional shapes and whose structure and structural dynamics directly influence their specific function. Most proteins have a primary, secondary and tertiary structure, but some of them, like hemoglobin, also have a quaternary structure. The primary structure of a protein is represented by the ordered succession of its amino acids held together by covalent bonds. While in nature amino acids may possess either the D or L configuration, amino acids within proteins almost exclusively possess the latter, as this allows proteins to have binding sites with three-dimensional properties matching those of their ligands. From an evolutionary standpoint, the existence of D-amino acids in certain proteins and peptides is highly beneficial since many D-amino acid-containing peptides participate in defense roles. This group includes antibiotic activities of secreted peptides against neighboring bacteria as well as toxic effects of psycho-active peptides on larger predators. The mode of action for these peptides involves their insertion into another organism that often possesses defense mechanisms based on stereo-specific recognition, like in the case of proteolytic enzymes and antibodies. The presence of D-amino acids prevents the host’s defense system from recognizing and degrading the peptide (Kesssel,A. and Ben-Tal N. (2011) Introduction to Proteins: Structure, Function and Motion, London: CRC Press). Certain portions of the amino acid chain tend to fold into... ... middle of paper ... ...orrect function, as it allows molecular recognition. Works Cited (Kesssel,A. and Ben-Tal N. (2011) Introduction to Proteins: Structure, Function and Motion, London: CRC Press) ( Travaglini-Allocatelli C; Ivarsson Y, Jemth P, Gianni S (2009) Folding and stability of globular proteins and implications for function, Current Opinion in Structural Biology 19 (1): 3–7). .( Ali, M.H and Imperiali, B. (2005) Protein oligomerization: how and why. Bioorganic and Medicinal Chemistry 13: 5013-20.) (Ponstingl, H., Kabir, T., Gorse, D., Thornton, J.M., (2005) Morphological aspects of oligomeric protein structure, Progress in Biophysics and Molecular Biology 89: 9-35). (Hardison, R. (1999) The Evolution of Hemoglobin: Studies of a very ancient protein suggest that changes in gene regulation are an important part of the evolutionary story, American Scientist, 87 (2): 126).
Macromolecules are define as large molecules of structures found in living organisms. There are four types of macromolecules, which are proteins, carbohydrate, nucleic acid, and lipids also known as fats. Carbohydrates, proteins, and nucleic acids are made of monomers, which are structural units that eventually attached together to form polymers (Dooley 20). For instance, proteins are made of amino acids, which are monomers. In addition, it has a complex structure, which consist of four different levels, primary, secondary, tertiary, and quaternary. The first structure of protein is the primary structure, which is the sequence of amino acid, while in the secondary structure alpha and beta helices are formed. The structure, in which a protein becomes active, is in the tertiary structure, which is where polypeptide subunits fold. Meanwhile, only certain proteins have the quaternary structure, which is when, more than one polypeptide folds. Proteins are prominent macromolecules mainly because of their numerous functions. For instance, proteins are known for increasing the rate of reactions due to that enzymes are a type of protein. In addition, they are a form of defense mechanism such as they attack pathogens, which cause diseases. In other words, scientists study and gain more insight on certain illness and how to prevent them by using proteins. For example, in a recent study,
The monomers that make up proteins are amino acids, and these proteins can be found in the cytoplasm of a cell while other proteins are found in the cell membrane. Proteins can be found in both prokaryotic and eukaryotic cells, similar to lipids and nucleic acids. The function of proteins is to organize the cell, cleanup waste, and determine the cell shape. The elements that make up a protein are hydrogen, nitrogen, oxygen, and carbon. A good example for protein is chicken, it contains high-quality protein which is protein that has the eight essential amino
CP consists of a single domain with high α-helical content [4]. The N-terminal part this domain is surface exposed whereas the C-terminal region buried in the virion. Several experiments indicate the CP is an O-glycoprotein. Equal amounts of galactose and fructose residues are O-linked to an acetylated serine residue at the N-terminal region [2]. This mediates the formation of a structured...
Protein have connection with amino acid to help in functions of: skin, muscle, hair and bones
Voet, D., Voet, J., & Pratt, C. (2006). Fundamentals of Biochemistry: Life at the Molecular Level, 2nd edition. Hoboken, NJ: John Wiley & Sons, Inc.
Amino acids are the building blocks of all proteins, which are complex molecules containing elements such as nitrogen, oxygen, carbon and hydrogen. Amino acids linked by peptide bonds create polypeptides. When there are many polypeptides linked together in a chain, and it is folded to fit a particular function, it creates a protein. However if it was not folded into a certain shape, it would not become a protein, rather just a Polypeptide.
Myoglobin consist of single polypeptide chain that made up of 153 amino acid and ahs a size of 18 kDa. Its three-dimensional structure was first determined by X-ray crystallography by John Kendrew in 1957. Myoglobin is a typical globular protein in that it is a highly folded compact structure with most of the hydrophobic amino acid residues buried in the interior and many of the polar residues on the surface. X-ray crystallography revealed that the single polypeptide chain of myoglobin consist of entirely of eight (labelled A-H) alpha-helical. Within a hydrophobic crevice formed by the folding polypeptide chain is the heme prosthetic group. This nonopolypepetide unit is noncovalently bound to myoglobin and is essential for the biological activity of the protein.
In summary, this excerpt went over how proteins are a linear polymer of amino acids linked together by peptide bonds. There are various interactions between the amino acids, which are mostly non-covalent, that stabilize the structure of a folded protein. There are 20 unique amino acids found naturally and can be grouped into three categories based off the nature of their R groups located on the side of the amino acids. Hydrophilic, hydrophobic or amino acids with a special R group which are composed of cysteine, glycine and proline. The Alpha helix and beta sheet are the most abundant structures of protein secondary structures. These stabilize hydr...
Proteins are essential to cells. They are found in eukaryotic cells. They help cells maintain their shape. They are essential in humans’ immune systems and all over the body. Amino acids are what go into proteins. There are 20 different types of Amino acids. Nine of them are essential and eleven are non-essential. Peoples body mass is made up with 15% of proteins. Each protein has a certain “job.” Hydrogen bonds, Ionic bonds or covalent bonds are formed in a protein molecule.
In the hierarchial organisation of proteins, domains are found at the highest level of tertiary structure. Since the term was first used by Wetlaufer (1973) a number of definitions exist reflecting author bias, however all of the definitions agree that domains are independently folding compact units. Domains are frequently coded by exons and therefore have specific functionality. Among the many descriptions of protein domains the two most striking and simple are " Protein evolutionary units" and "Basic currency of Proteins".
Many proteins are the most prominent structural motif of the functional protein in its native conformation known as the alpha helix (Pauling et al. 1951). When a protein follows the wrong folding pathway, the protein misfolds and becomes a toxic configuration. When a protein becomes toxic, it obtains a motif known as the beta sheet. Although the beta sheet conformation also exists in many functional native proteins, the abnormal conformational change from alpha helix to beta sheet exposes
Protein is considered one of the three nutrients that are able to provide calories to the body, with the other two as fat and carbohydrates. Proteins function as building blocks for bones, muscles, cartilage, skin, and blood (US Department of Agriculture, n.d., p. 1). Even after that, they continue to benefit the body in terms of enzymes, hormones, and vitamins. Construction, maintenance, and fixation of body tissues highly de...
Proteins are a fundamental macromolecule, playing an essential role in the creation of life, coded for by genes in DNA. Proteins have a wide range of functions in the body, with perhaps the most significant being their role as enzymes. It is these enzymes that are responsible for the biological catalysis of almost all essential cellular reactions that constitute basic life. This range would not be possible without their diversity in structure, as a protein’s structure is directly linked to its functions. Proteins are able to achieve this variety by having a four-tiered structural ‘hierarchy’ with four layers of structure; primary, secondary, tertiary and
There are four main levels of a protein, which make up its native conformation. The first level, primary structure, is just the basic order of all the amino acids. The amino acids are held together by strong peptide bonds. The next level of protein organization is the secondary structure. This is where the primary structure is repeated folded so that it takes up less space. There are two types of folding, the first of which is beta-pleated sheets, where the primary structure would resemble continuous spikes forming a horizontal strip. The seco...
Molecular docking is used to predict the structure of the intermolecular complex formed between two or more molecules. The most interesting case is the protein-ligand interaction, because of its applications in medicine. Ligand is a small molecule, which interacts with protein’s bind...