Show Advanced Search

REFINE YOUR SEARCH:

Containing Text
- - -
+
Filter by author or institution
GO
Filter by publication date
From:
October, 2006
Until:
Today
Filter by journal section

Filter by science education

 
 
Protein Folding: Processes involved in the formation of Tertiary protein structure.

Protein Folding

JoVE 10679

Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation which is critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.

Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing immunological defense, storage, transport, cellular communication, movement, and structural support. A protein’s function mostly depends on its ability to recognize and bind other molecules, analogous to a lock and key. Hence the specific activity of each protein depends on its unique three-dimensional architecture. For a protein to be functional, it must fold accurately. Most proteins go through several intermediate forms before folding into the most stable, biologically active structure. Misfolding of proteins has detrimental effects on the overall functioning of the cell. In humans, several diseases are due to the accumulation of misfolded or unfolded proteins. These include cystic fibrosis, Alzheimer’s, Parkinson’s, ALS, and Creutzfeldt-Jakob disease. Proteins are made up of one or more chains of amino acids, called polypeptides. A polypeptide is synthesized as a linear chain which rapid

 Core: Macromolecules

Protein Associations

JoVE 10704

The cell membrane—or plasma membrane—is an ever-changing landscape. It is described as a fluid mosaic as various macromolecules are embedded in the phospholipid bilayer. Among the macromolecules are proteins. The protein content varies across cell types. For example, mitochondrial inner membranes contain ~76%, while myelin contains ~18% protein content. Individual cells contain many types ofbrane proteins—red blood cells contain over 50—and different cell types harbor distinct membrane protein sets. Membrane proteins have wide-ranging functions. For example, they can be channels or carriers that transport substances, enzymes with metabolic roles, or receptors that bind to chemical messengers. Like membrane lipids, most membrane proteins contain hydrophilic (water-loving) and hydrophobic (water-fearing) regions. The hydrophilic areas are exposed to water-containing solution inside the cell, outside the cell, or both. The hydrophobic regions face the hydrophobic tails of phospholipids within the membrane bilayer. Membrane proteins can be classified by whether they are embedded (integral) or associated with the cell membrane (peripheral). Most integral proteins are transmembrane proteins, which traverse both phospholipid layers, spanning the entire membrane. Their hydrophilic regions extend from both sides of the membrane, facing cytosol on

 Core: Membranes and Cellular Transport

Cytoplasm

JoVE 10967

The cytoplasm consists of organelles, an aqueous solution called the cytosol, and a framework of protein scaffolds called the cytoskeleton. The cytosol is a rich broth of ions, small organic molecules such as glucose, and macromolecules such as proteins. Several cellular processes including protein synthesis occur in the cytoplasm.

The composition of the cytosol promotes protein folding such that hydrophobic amino acid side chains are oriented away from the aqueous solution and towards the protein core. However, cellular stressors such as aging and changes in pH, temperature, or osmolarity cause protein misfolding. Misfolded proteins may aggregate to form insoluble deposits in the cytoplasm. Insoluble protein aggregates are implicated in neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. The eukaryotic cytoskeleton consists of three types of filamentous proteins: microtubules, microfilaments, and intermediate filaments. Microtubules–the largest type of filament–are made up of the protein tubulin. Microtubules are dynamic structures that can grow or shrink by adding or removing tubulin molecules from the ends of their strands. They provide structural stability and provide tracks for the transport of proteins and vesicles within the cell. In addition, microtubules play a

 Core: Cell Structure and Function

Chemically-blocked Antibody Microarray for Multiplexed High-throughput Profiling of Specific Protein Glycosylation in Complex Samples

1Institute for Hepatitis and Virus Research, 2Department of Microbiology and Immunology, Thomas Jefferson University, 3Drexel University College of Medicine, 4Van Andel Research Institute, 5Institute for Hepatitis and Virus Research, Serome Biosciences Inc.

JoVE 3791

 Biology

Development of Recombinant Proteins to Treat Chronic Pain

1Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht University, 2Department of Rheumatology & Clinical Immunology, University Medical Center Utrecht, Utrecht University, 3Laboratory of Neuroimmunology and Developmental Origins of Disease, University Medical Center Utrecht, Utrecht University

JoVE 57071

 Medicine

Enhanced Genome Editing with Cas9 Ribonucleoprotein in Diverse Cells and Organisms

1Department of Molecular Cell Biology, University of California, Berkeley, 2Howard Hughes Medical Institute, University of California, Berkeley, 3Innovative Genomics Institute, University of California, Berkeley, 4Biomedical Sciences Graduate Program, University of California, San Francisco, 5Department of Microbiology and Immunology, University of California, San Francisco, 6Diabetes Center, University of California, San Francisco, 7Chan Zuckerberg Biohub, 8Department of Medicine, University of California, San Francisco, 9UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 10Department of Integrative Biology, University of California, Berkeley

JoVE 57350

 Genetics

Atomic Absorbance Spectroscopy to Measure Intracellular Zinc Pools in Mammalian Cells

1Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 2Department of Chemistry, Skidmore College, 3Candiac MR Center, Beth Israel Deaconess Medical Center, 4Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero

JoVE 59519

 Biochemistry

Spontaneous Formation and Rearrangement of Artificial Lipid Nanotube Networks as a Bottom-Up Model for Endoplasmic Reticulum

1Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, 2Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Oslo, 3Department of Chemistry and Chemical Engineering, Chalmers University of Technology

JoVE 58923

 Bioengineering
123
More Results...