Term
| number of standard amino acids in proteins |
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Definition
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Definition
-chemical reactions
-structure and support
-channels and pumps
-communication and signaling
-motion/movement |
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Definition
-sequence of amino acids in a polypeptide chain
-consists of polypeptide backbone
-R-groups |
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Definition
-similar amino acid sequences that have arisen from a common ancestral gene
-generally same function in cells |
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Term
| shape of a protein/basis for diversity is determined by |
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Definition
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Term
| determine the folding of amino acids |
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Definition
-covalent/noncovalent bonds
-side chain (R-group) |
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Term
| can restrict possible arrangement of atoms/folding of proteins |
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Definition
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Term
| proteins will for in a way to |
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Definition
-localized 3D arrangement of adjacent amino acids in the protein structure
-alpha/beta |
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Term
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Definition
-single polypeptide chain
-H-bond between every 4th peptide bond
-complete turn every 3.6 amino acids
-common in transmembrane proteins
-exterior amino acids with nonpolar side chains
-interior helix is H-bonded shielded from lipids |
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Term
| amino acids generally not found in secondary structure |
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Definition
-Gly (too small R-group_
-Pro (rigid ring prevents rotation)
-charged/bulky side chains |
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Term
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Definition
-strands of amino acids interacting laterally
-each NH and CO bond are H bonded
-parallel or antiparallel
-rigid structure
-large and branched amino acids tend to be in the middle of the beta sheets
-in the core of many proteins |
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Term
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Definition
-full 3D organization of a polypeptide chain
-folding into a biologically active unit
-interactions btw primary and secondary structure (alpha/beta/side chains)
-collection of all primary and secondary strutures WITHIN THE SAME CHAIN |
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Term
| important features of tertiary structure |
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Definition
-polypeptides may fold so that amino acids distant come close
-certain proteins are compact because efficient packing (most water molecules excluded from interior)
-tertiary structure can take MANY shapes but each will only take one shape
-large (200+ amino acids) proteins often contain different compact units (domains) |
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Term
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Definition
-many proteins especially of high molecular weight are composed of multiple polypeptide chains
-arrangement that subunits assemble
-interactions are non-covalent and disulfide bonds |
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Term
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Definition
| single protein molecule that assembles with other protein subunits to form a protein complex |
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Term
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Definition
| one composed of two or more protein subunits |
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Term
| possible reasons for multi-subunit proteins |
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Definition
-synthesis of subunits maybe be more efficient
-replacement of damaged components can be managed more efficiently
-interactions of subunits may help regulate biological function of proteins
-evolutionary processes allowed for interaction of proteins that were previously separate, leading to new improved functions |
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Term
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Definition
-unit of organization distinct from hierarchical levels
-structurally independent segments that have specific functions
-can fold independently into a compact stable structure (A/B/both)
-different domains=different functions
-homology in domains is apparent in different proteins and species |
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Term
| functions of protein domains |
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Definition
-catalytic (enzymes)
-regulatory
-locomotion
-transport
-structural
-binding
-formation of assemblies (quaternary) |
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Term
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Definition
-Tyr/kinase
-SH2 and SH3 domains regulate the activity of SRC
-c-terminal domain possess catalytic activity |
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Term
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Definition
| bind and regulate what is transcribed |
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Term
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Definition
-small Hsps
-chaperones
-chaperonins |
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Term
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Definition
| small, mainly prevent aggregation and degradation |
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Term
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Definition
-larger,named by mass (Hsp70)
-stabilization, prevent aggregation, sometimes assist in folding |
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Term
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Definition
-oligomeric chambers
-assist in protein folding |
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Term
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Definition
-group I chaperonin found in mitochondria
-once an unfolded protein is released from an HSP70, it is passed on to an HSP60 which mediates PROTEIN FOLDING
-large structures composed of two stacked rings
-cavity inside has rings of alternating hydrophobic/philic character driven by ATP
-unfolded protein enters cavity |
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Term
| different environments can effect protein folding |
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Definition
-free energy difference between a folded and unfolded confirmation of a protein is often quite small
-protein folding is sensitive to small environmental changes (denaturation) |
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Term
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Definition
-strong acids/bases
-organic solvents
-salts
-metal ions
-temperature changes |
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Term
| strong acids/bases denaturing |
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Definition
-alters protonation
-proteins become less soluble as pH approaches isoelectric point |
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Term
| organic solvents (water soluble) denaturing |
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Definition
| -disrupt balance of hydrophobic/philic bonds |
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Term
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Definition
| -some salts attract water and decrease interactions between water molecules and polar protein side chains |
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Term
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Definition
| -bind to various groups in and on proteins disrupting normal structure |
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Term
| temperature changes denaturing |
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Definition
| -increase molecular vibrational energy which can disrupt H-bonds |
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Term
| more denaturing conditions |
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Definition
-detergents
-reducing agents
-mechanical stress |
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Term
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Definition
| -as surfactants they disrupt balance of hydrophobic/philic interactions |
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Term
| reducing agents denaturing |
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Definition
| -converts disulfide bonds to sufhydryl groups |
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Term
| mechanical stress (stirring,sonication) denaturing |
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Definition
| -disrupts weak interactions |
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