Proteins primary, secondary and tertiary structure

MOLECULAR SHAPE OE PROTEINS PRIMARY, SECONDARY AND TERTIARY STRUCTURES... 

Molecular shape of proteins primary, secondary and tertiary structures... 

C13-0031. Define primary, secondary, and tertiary structure. Give examples of each type of structure for a protein and for DNA. 

Amongst the secretions of specialised exocrine complexes, the ancillary products which act as sticky compounds are large, often proteinaceous, molecules. Their primary, secondary and tertiary structures being inherently complex are now seen as ideal informational vehicles — alone or in combination with volatile molecules. Much recent work (Sec. 3.2, below) has identified them as the key components involved in close range transmission, and in intra-nasal peri-receptor events. Proteins are semiochemically implicated when their selective removal or presentation alters responsiveness (Belcher et al., 1990 Mucignat-Caretta et al, 1995). 

Evolutionary processes driven by environmental changes and varying conditions have an impact on all components in a living cell. Thus, the primary, secondary and tertiary structure of proteins determines their function and location, giving different properties in different compartments, such as outer membrane, periplasmic space, cytoplasmic membrane or cytoplasm. Proteins can function as monomers or oligomers and can occur in a soluble form, as integral constituents embedded within the membrane, or can be found associated with the lipid bilayer itself or components therein. 

Increasing evidence suggests that evolution has used (and is using) the E2 fold for new purposes. In one apparent example of functional expansion, E2 core domains have been observed to be embedded within much larger polypeptide chains [140, 141]. The functional properties of these massive E2s remain poorly characterized, and it is likely that more of them will be discovered. But the clearest case of functional diversification is provided by the UEV proteins. UEVs are related to E2s in their primary, secondary, and tertiary structures, but they lack an active-site cysteine residue and therefore cannot function as canonical E2s [142]. Nonetheless they play several different roles in ubiquitin-dependent pathways. 

Since the early 1960s, when it was shown that ribosomes contain a large number of different proteins, a tremendous effort has been made to isolate and characterize each individual protein. The first problem was to prepare individual, homogeneous proteins. Determination of the primary, secondary, and tertiary structure, as well as of the overall physical characteristics, was then approached. 

Distinguish among the primary, secondary, and tertiary structures of this protein. 

The stereochemical specificity of enzymes depends on the existence of at least three different points of interaction, each of which must have a binding or catalytic function. A catalytic site on the molecule is known as an active site or active centre of the enzyme. Such sites constitute only a small proportion of the total volume of the enzyme and are located on or near the surface. The active site is usually a very complex physico-chemical space, creating micro-environments in which the binding and catalytic areas can be found. The forces operating at the active site can involve charge, hydrophobicity, hydrogen-bonding and redox processes. The determinants of specificity are thus very complex but are founded on the primary, secondary and tertiary structures of proteins (see Appendix 5.1). 

Distinguish between the primary, secondary and tertiary structure of proteins. Which is usually responsible for the geometry and properties of the substrate binding site How are the properties of the binding site reflected by the induced fit model ... 

Proteins come in many different sizes and shapes. For example, cytochrome c, a protein that transfers electrons, has only one polypeptide chain of 104 amino acids. Yet myosin, the protein that makes muscles contract, has two polypeptide chains with some 2,000 amino acids each, connected by four smaller chains. It is called a multimeric protein. No matter their size, all proteins have a primary, secondary, and tertiary structure. Some also have quaternary structure. 

Nucleic acids have a primary, secondary, and tertiary structure analogous to the classification of protein structure. The sequence of bases in the nucleic acid chain gives the primary structure of DNA or RNA. The sequence of bases is read in a 5 -> 3 direction, so that you would read the structure in the next figure as ACGT. See Figure 8-1. 

The potentiality of a protein to cause an allergic reaction is related to the size of the protein, its primary, secondary and tertiary structures. Antigenicity of casein hydrolysate prepared by using pancreatic proteases was studied by Mahmoud et al. (1992). 

The NMR studies of proteins lead to information about their primary, secondary, and tertiary structure as well as information about their interactions with substrates. 

The study by Determan et al. [224] focuses on the effects of polymer degradation products on the primary, secondary, and tertiary structure of TT, OVA, and lysozyme after incubation for 0 or 20 days in the presence of ester (lactic acid and glycolic acid) and anhydride [sebacic acid and l,6-bis(p-carboxyphenoxy)hexane] monomers. The structure and antigenicity or enzymatic activity of each protein in the presence of each monomer was quantified. SDS-PAGE, circular dichroism, and fluorescence spectroscopy were used to assess/evaluate the primary, secondary, and tertiary structures of the proteins, respectively. ELISA was used to measure changes in the antigenicity of TT and OVA and a fluorescence-based assay was used to determine the enzymatic activity of lysozyme. TT toxoid was found to be the most stable in the presence of anhydride monomers, while OVA was most stable in the... 

Eisenhaber, F Persson, B. Argos, P. (1995). Protein structure prediction recognition of primary, secondary, and tertiary structural features from amino acid sequence. Crit Rev Biochem Mol Biol 30,1-94. 

All enzyme molecules possess the primary, secondary, and tertiary structural characteristics of proteins (see Chapter 20). In addition, most enzymes also exhibit the quaternary level of structure. The primary structure, the linear sequence of amino adds linked through their a-carboxyl and a-amino groups by peptide bonds, is specific for each type of enzyme molecule. Each polypeptide cham is coiled up into three-dimensional secondary and tertiary levels of structure. Secondary structure refers to the conformation of limited segments of the polypeptide chain, namely a-helices, P-pleated sheets, random coils, and p-turns. The arrangement of secondary structural elements and amino acid side chain interactions that define the three-dimensional structure of the folded protein is referred to as its tertiary structure. In many cases biological activity, such as the catalytic activity of enzymes, requires two or more folded polypeptide chains (subunits) to associate to form a functional molecule. The arrangement of these subunits defines the quaternary structure. The subunits may be copies of the... 

The present use of the terms primary, secondary, and tertiary structure for mucins does not necessarily correspond to their usage as api ed to proteins. 

Protein molecules are described in terms of their primary, secondary, and tertiary structures. The primary structure of a protein is the linear sequence of its amino acids. The primary structure for BPTI is... 

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