1.3 Proteins Flashcards
α-helix
definition: a prevalent type of protein secondary structure
description: a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O
stabilized by: hydrogen bond between CO and NH groups of the main chain to stabilize.
formed by: formed by hydrogen bonds within protein strands
β-pleated sheet
definition: series of anti-parallel chains of covalently-linked amino acids, with adjacent chains linked by hydrogen bonds.
description: The regular folding of each amino acid chain leads to a regular pleated pattern across chains.
stabilized by:
formed by: formed by hydrogen bonds between protein strands
•Amino acid
monomeric units that are teh buildingblokcs of protein; that are capable of existing in ionized and unionized forms composed of: 1. amino group 2. alpha carbon 3. r-group side chain 4. hydrogen atom 5. carboxyl group
C-terminus
the end of the peptide chain aka the 5’ end of the chain
Chaperones
a protein that assists the folding/assembly of other proteins.
Condensation reaction
Monomers polymerize through condensation reactions
Denaturation
Definition: structural change in a protein (caused by either pH or temp) that results in the loss (usually permanent) of its biological properties
Because the way a protein folds determines its function, any change or abrogation of the tertiary structure will alter its activity
- —>temp
1. High levels of thermal energy may disrupt the hydrogen bonds that hold the protein together
2. As these bonds are broken, the protein will begin to unfold and lose its capacity to function as intended
3. Temperatures at which proteins denature may vary, but most human proteins function optimally at body temperature (~37ºC)
Dimer
a macromolecular complex formed by two protein monomers
Disulfide bonds
an S-S bond, or disulfide bridge, is a covalent bond derived from two thiol groups
Folding
the process by which a protein structure assumes its functional shape or conformation
Hydrolysis
these reactions involve the breaking of polymers into individual monomers by splitting water
Macromolecule
a very large molecule, such as a protein
Monomer
these subunits polymerize thru condensation reactions
Oligopeptide
a short peptide chain used to refer to peptides with less than 20–25 amino acid residues.
Peptide bond
The carboxyl group of one amino-acid reacts with the amino group of another to form this type of bond
Polymer
3 classes of macromolecules are ____
which are composed of repeating subunits called monomers that are covalently bonded together
Polymerization
process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer.
Polypeptide
a chain of many amino acids
Primary structure•
the unique sequence of amino acids residues in a protein
description: amino acid monomers are joined, forming polypeptide chains
stabilized by: peptide bonds
Protein•
are long polymers containing many freely rotating binds which allow for tremendouse confirmational flexibilty
monomer: amino acid
bond type: peptide bond
Quaternary structure•
the overall 3d shaped formed from 2 or more polypeptide chains (subunits)
description: 2 or more polypeptides assmeble to form larger protein molecules
stabilized by: h-bonds, ionic interactions, hydrophobic interactions, disulfide brdiges
R-group•
a side chain specific to each amino acid that confers particular chemical properties to tha
Residue
Any of the monomers comprising a polymer
Secondary structure•
the localized fooding of a polypeptide chain into regualr structures (alpha helices and beta-pleated sheets)
description: polypeptide chains may form a-helices or B-pleated sheets
stabilized by: h-bonds between components of the peptide backbone results in secondary structure