Biological Products: Molecular Structure and Function

2021 ◽  
pp. 130-157
Keyword(s):  
Mammalian Cells ◽  
Living Cells ◽  
Structure And Function ◽  
Peptide Bonds ◽  
Biological Products ◽  
Whole Cells ◽  
Drug Products ◽  
Small Molecule Drugs ◽  
And Function ◽  
Molecular Structure And Function

This chapter analyses biological products that are defined by the method of manufacture and distinguished by a production process that separates biological drug products from orthodox, ‘small molecule’ drugs. It explains how biological products are synthesised by a variety of living cells, such as bacteria, fungi, or mammalian cells. It also refers to the types of modern biological therapies that range among proteins, nucleic acids, and whole cells. The chapter discusses monoclonal antibodies, which is considered the largest class of biological products in clinical use and are designed to attach to diseased cells, like cancer cells, that are expressing abnormal proteins on their surface. It describes proteins as chains of amino acids linked to each other chemically by peptide bonds, hence the alternative term ‘polypeptides’.

Expanding the genetic code of mammalian cells

2017 ◽  
Vol 45 (2) ◽  
pp. 555-562 ◽  
Author(s):  
James S. Italia ◽  
Yunan Zheng ◽  
Rachel E. Kelemen ◽  
Sarah B. Erickson ◽  
Partha S. Addy ◽  
...  
Keyword(s):  
Protein Structure ◽  
Amino Acid ◽  
Mammalian Cells ◽  
Living Cells ◽  
Structure And Function ◽  
Unnatural Amino Acid ◽  
Full Potential ◽  
Recent Developments ◽  
Small Footprint ◽  
And Function

In the last two decades, unnatural amino acid (UAA) mutagenesis has emerged as a powerful new method to probe and engineer protein structure and function. This technology enables precise incorporation of a rapidly expanding repertoire of UAAs into predefined sites of a target protein expressed in living cells. Owing to the small footprint of these genetically encoded UAAs and the large variety of enabling functionalities they offer, this technology has tremendous potential for deciphering the delicate and complex biology of the mammalian cells. Over the last few years, exciting progress has been made toward expanding the toolbox of genetically encoded UAAs in mammalian cells, improving the efficiency of their incorporation and developing innovative applications. Here, we provide our perspective on these recent developments and highlight the current challenges that must be overcome to realize the full potential of this technology.

scholarly journals Deglycosylation of glycoproteins with trifluoromethanesulphonic acid: elucidation of molecular structure and function

2003 ◽  
Vol 376 (2) ◽  
pp. 339-350 ◽  
Author(s):  
Albert S. B. EDGE
Keyword(s):  
Molecular Structure ◽  
Peptide Bond ◽  
Structure And Function ◽  
Glycosidic Linkage ◽  
Biological Functions ◽  
Peptide Bonds ◽  
Post Translational Modifications ◽  
And Function ◽  
Carbohydrate Chains ◽  
Molecular Structure And Function

The alteration of proteins by post-translational modifications, including phosphorylation, sulphation, processing by proteolysis, lipid attachment and glycosylation, gives rise to a broad range of molecules that can have an identical underlying protein core. An understanding of glycosylation of proteins is important in clarifying the nature of the numerous variants observed and in determining the biological roles of these modifications. Deglycosylation with TFMS (trifluoromethanesulphonic acid) [Edge, Faltynek, Hof, Reichert, and Weber, (1981) Anal. Biochem. 118, 131–137] has been used extensively to remove carbohydrate from glycoproteins, while leaving the protein backbone intact. Glycosylated proteins from animals, plants, fungi and bacteria have been deglycosylated with TFMS, and the most extensively studied types of carbohydrate chains in mammals, the N-linked, O-linked and glycosaminoglycan chains, are all removed by this procedure. The method is based on the finding that linkages between sugars are sensitive to cleavage by TFMS, whereas the peptide bond is stable and is not broken, even with prolonged deglycosylation. The relative susceptibility of individual sugars in glycosidic linkage varies with the substituents at C-2 and the occurrence of amido and acetyl groups, but even the most stable sugars are removed under conditions that are sufficiently mild to prevent scission of peptide bonds. The post-translational modifications of proteins have been shown to be required for diverse biological functions, and selective procedures to remove these modifications play an important role in the elucidation of protein structure and function.

Oxidative protein folding in the mammalian endoplasmic reticulum

2004 ◽  
Vol 32 (5) ◽  
pp. 655-658 ◽  
Author(s):  
C.E. Jessop ◽  
S. Chakravarthi ◽  
R.H. Watkins ◽  
N.J. Bulleid
Keyword(s):  
Endoplasmic Reticulum ◽  
Mammalian Cells ◽  
Redox State ◽  
Structure And Function ◽  
Reduced Form ◽  
Secretory Proteins ◽  
Oxidative Protein Folding ◽  
Disulphide Bonds ◽  
And Function ◽  
Substrate Proteins

Native disulphide bonds are essential for the structure and function of many membrane and secretory proteins. Disulphide bonds are formed, reduced and isomerized in the endoplasmic reticulum of mammalian cells by a family of oxidoreductases, which includes protein disulphide isomerase (PDI), ERp57, ERp72, P5 and PDIR. This review will discuss how these enzymes are maintained in either an oxidized redox state that allows them to form disulphide bonds in substrate proteins or a reduced form that allows them to perform isomerization and reduction reactions, how these opposing pathways may co-exist within the same compartment and why so many oxidoreductases exist when PDI alone can perform all three of these functions.

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