P3.2. Protein Flashcards
- naturally-occurring
- unbranched polymer in which the monomer units are amino acids
PROTEIN
Elemental Compositon of Protein:
Carbon
Hydrogen
Oxygen
Nitrogen
may also contain Sulfur
average nitrogen content of proteins
15.4% by mass
Some elemental composition that can be present in proteins are:
Fe, P, and some other metals in some specialized protein
a peptide in which at least 40 amino acid residues are present
PROTEIN
Several proteins with ____ amino acid residues are known
GREATER THAN 10,000
Common proteins contain ____ amino acid residues
400–500
Small proteins contain ____ amino acid residues
40–100
TRUE OR FALSE?
There can be more than one peptide chain may be present in a protein.
TRUE
contains one peptide chain
monomeric protein
contains more than one peptide chain
multimeric protein
2 PROTEIN CLASSIFICATION BASED ON CHEMICAL COMPOSITION:
Simple Proteins
Conjugated Proteins
- only amino acid residues are present.
- more than one protein MAY BE PRESENT, but ALL SUBUNITS contain only AMINO ACIDS.
protein portion - AMINO ACIDS
Simple Proteins
A protein that has one or more non-amino acid entities (prosthetic groups) present in its structure
Conjugated Protein
- non-amino acid entities are ____.
- non-amino acids components may be ____.
- prosthetic groups
- organic/inorganic - prosthetic groups
Examples of Prosthetic Groups:
- Lipoproteins
- Glycoproteins
- Metalloproteins
TRUE OR FALSE?
One or more polypeptide chains may be present in Conjugated Proteins.
TRUE
TRUE OR FALSE
Non-amino acid components in Conjugated protein may be organic or inorganic prosthetic groups.
TRUE
contain lipid prosthetic groups
Lipoproteins
contain carbohydrate groups
Glycoproteins
contain a specific metal as prosthetic group
Metalloproteins
Four types of Protein Structures:
- PRIMARY STRUCTURE
- SECONDARY STRUCTURE
- TERTIARY STRUCTURE
- QUATERNANRY STRUCTURE
these four dictates the function & defines the morphology of proteins
refers to the order [number and sequence] in which amino acids are linked together in a protein
PRIMARY STRUCTURE OF PROTEINS
the number and sequence of amino acids linked by the amides/peptide bonds are dictated by?
DNA CODING
sequenced and determined the primary structure for the first protein hormone - Insulin
its:
- molecular structure
- identity
- binding capacity/ability
Frederick Sanger (1953)
- interaction of adjacent amino acids
its 3 forms?
SECONDARY STRUCTURE OF PROTEINS
- alpha-helix [spring]
- beta-pleated [corugated form]
- random [without pattern]
The peptide linkages [in SECONDARY STRUCTURE of Proteins] are essentially ____ thus allows only two possible arrangements for the peptide backbone
planar
The peptide linkages [in SECONDARY STRUCTURE of Proteins] are essentially planar thus allows only two possible arrangements for the peptide backbone…
ITS REASONS:
- For two amino acids linked through a peptide bond six atoms lie in the same plane
- The planar peptide linkage structure has considerable rigidity, therefore rotation of groups about the C–N bond is hindered
- Cis–trans isomerism is possible about C–N bond.
- The trans isomer is the preferred orientation
yung naka-bold lang tandaan HAHAHAHA. Explain in own words na langs~
- single protein chain
- shape: COILED SPRING [HELIX]
- coiled helical spring
- its R-group are outside the Helix because there is not enough room for them to stay inside.
- H-bonding between same amino acid chains – INTRAMOLECULAR
SAME AMINO ACIDS - HYDROGEN BONDING
R-GROUP OUTSIDE!!!
Alpha-helix (a-helix)
- Completely extended amino acid chains
- Side chains below or above the axis
- H-bonding between two different chains – INTER or/and INTRAMOLECULAR
DIFFERENT AMINO ACIDS - HYDROGEN BONDING
R-GROUP/SIDE CHAINS - TOP OR BOTTOM!!!
Beta-pleated sheets (b-pleated sheet)
- overall three-dimensional shape of a protein
- interactions between amino acid side chains (R groups) that are widely separated from each other
- defines the physical & chemical properties of proteins
TERTIARY STRUCTURE OF PROTEINS
4 types of interactions are observed in Tertiary Structure of Proteins:
- Disulfide Bond
- Electrostatic Interactions
- H-bondings
- Hydrophobic interactions
- covalent
- strong
- between two cysteine groups
Disulfide Bond
- Salt Bridge between charged side chains of acidic and basic amino acids
Electrostatic Interactions
-OH
-NH2
-COOH
-CONH2
- bonding between polar, acidic and/or basic R groups
- for this bonding to occur, it must be attach to what elements?
- H-bonding (Hydrogen Bonding)
- OXYGEN, NITROGEN, FLUORINE
interaction between non-polar side chains.
Hydrophobic Interactions
- HIGHEST level of protein organization.
- 2 or more chains/subunits attract to form proteins.
QUATERNARY STRUCTURE OF PROTEINS
Most ____ contain an even number of subunits (two subunits a dimer, four subunits a tetramer, and so on).
multimeric proteins
held together mainly by hydrophobic interactions between amino acid R groups.
subunits
- example of a protein with quaternary structure.
- oxygen carrying protein in blood
- tetramer in which there are two identical a chains and two identical B chains
Each chain in this protein enfolds a ____, the site where oxygen binds to the protein.
Hemoglobin
heme group
Proteins Classification based on SHAPE:
- FIBROUS PROTEINS: Collagen
- GLOBULAR PROTEINS: Myoglobin & Hemoglobin
- Most abundant proteins in humans (30% of total body protein)
- Major structural material in CONNECTIVE TISSUES [tendons, ligaments, blood vessles, skin]
- Organic component of bones and teeth
- Predominant structure - TRIPLE HELIX
- Rich in proline (up to 20%) – important to maintain structure
COLLAGEN
Collagen is rich in what derivatives?
4-hydroxyproline (5%)
5-hydroxylysine (1%)
some hydroxylysines are linked to ____ and ____, and their ____ that helps in aggregation of collagen fibrils.
aggregation: cluster
- glucose
- galactose
- disaccharides
- oxygen storage molecule in muscles.
- Monomer - single peptide chain with one heme unit
- Binds one O2 molecule
- oxygen serves as a reserve oxygen source for working muscles
Myoglobin
TRUE or FALSE:
myglobin has a higher affinity for oxygen than hemoglobin.
TRUE
- An oxygen carrier molecule in blood
- Transports oxygen from lungs to tissues
- Tetramer (four peptide chains) - each subunit has a heme group
- Can transport up to 4 oxygen molecules at time
Iron atom in heme interacts w/…
Hemoglobin
Oxygen
PROTEINS CLASSIFICATION BASED ON FUNCTION:
- ability to bind small molecules
- ability to bind other proteins
- ability integrated into cell membranes
Proteins is the most versatile macromolecule.
