Protein Structure and Function Flashcards
Specialized group of proteins required for the PROPER FOLDING OF MANY SPECIES OF PROTEINS
Prevents aggregation and misfolding
Chaperones
Due to UNFOLDING AND DISORGANIZATION OF A PROTEIN
Denaturation
does NOT affect primary structure
Globular Proteins
hemoglobin myoglobin albumin globulin most enzymes
spherical
MORE soluble
has DYNAMIC functions
Fibrous Proteins
collagen fibers
elastin fibers
keratin
elongated or needle shaped
MINIMALLY soluble
STRUCTURAL proteins
Most abundant protein in the body
Collagen
3 polypeptides (alpha-chains) wound around in triple helix formation (stabilized by hydrogen bonds)
MC form of collagen
Type 1 collagen
Usual pattern of AA in collagen
Gly - glycine
X - proline
Y - hydroxyproline, hydroxylysine
Type I collagen
BONE
OI
Type 2 collagen
Cartilage
Achondrogenesis type II
Type 3 collagen
Reticulin fibers, blood vessels, granulation tissue
Ehlers Danlos (vascular type) aortic rupture, aortic aneurysms
Type 4 collagen
Basement Membrane
Alport Syndrome
Goodpasture Syndrome
Type 5 collagen
bone, skin, fetal tissues, placenta
Ehler Danlos (classical type)
Type 7 collagen
Anchoring fibrils
Dystrophic epidermolysis bullosa
Connective tissue with rubber like properties allowing extensibility and elastic recoil
Elastin
non hydroxylated PROLINE, LYSINE - major AA
Scaffold for the synthesis of elastin fibers
FIBRILLIN
Cross links precursor tropoelastin together
DESMOSINE
Defective in Marfan Syndrome
skeletal change aortic dissection ectopic lentis (upward, outward)
Fibrillin
Triad of Marfan’s Syndrome
Skeletal changes
Ectopic lentis - upward and temporal subluxatiob
aortic aneurysm
FIBRILLIN 1
zonular fibers in the lens
periosteum
aorta
International Criteria to classify Marfan syndrome
Ghent Criteria
Mutation in TGR Beta Receptors
Characterized by aortic aneurysms, cleft palate, hypertelorism
Loeys-Dietz
Alpha helix coiled structure wind arpund each other to form a super helix
Rich in HYDROPHOBIC AA - Ala, Leu, Met, Val, Phe
KERATIN
Major protein component of Renal Glomerular and other Basal Laminas
LAMININ
Glycosaminoglycans present in BASAL LAMINA
Heparin
Heparan sulphate
2 types of Protein Degradation
ATP Independent Degradation
ATP Dependent Degradation
Proteins that undergo ATP independent degradation
Extracellular proteins
Membrane-association proteins
Long-lived intracellular proteins
SITE: LYSOSOMES
i.e. blood glycoprotein
Proteins that undergo ATP dependent degradation
Regulatory proteins with short half lives
Abnormal or misfolded proteins
SITE: cytosol
requires UBIQUITIN
Key molecule in protein degradation
Highly conserved protein
UBIQUITIN
Ubiquinated proteins are degraded in
Proteosome - located in the CYTOSOL
Proteosome Inhibitor
Used in Multiple Myeloma
For Hepatocellular Carcinoma
Bortezomib
Maintain the colloid osmotic pressure of the plasma
ALBUMIN
Most abundant PLASMA PROTEIN
ALBUMIN
LEAST abundant PLASMA PROTEIN
alpha 1 globulin
Plasma protein with FASTEST electrophoretic mobility
PREALBUMIN (transthyretin)
Most plasma proteins are synthesized in the LIVER EXCEPT
Immunoglobulins - plasma cells
Most plasma proteins are glycoproteins EXCEPT
Albumin - simple protein
Plasma proteins that exhibit POLYMORHISM
a1 antitrypsin haptoglobin transferrin ceruloplasmin immunoglobulins
Group of Plasma proteins whose concentration increases or decreases in response to inflammatory and neoplastic conditions
ACUTE PHASE REACTANTS
Positive Acute Phase Reactants
concentration increases in response to inflammatory and neoplastic conditions
CRP Ceruloplasmin Haptoglobulin Fibrinogen alpha 1 acid glycoproteun alpha 1 antiprotease
Properties of proteins at ISOELECTRIC pH
they have NO net charge they do NOT have eletrophoretic mobility maximum precipitability maximum solubility minimum buffering action
Polypeptide formation in amino acid is by
PRIMARY STRUCTURE
Confirmatory test for proteins
Western Blot
ELISA
Chip assay
Dot blot
2 Important Phosphoproteins
CASEIN (milk)
OVOVITELLIN ( egg yolk)
An alpha helix of a protein is most likely be disrupted if a missense mutation introduces the ff AA within the alpha helical structure
GLYCINE
Molecules up to size 4 KD is identified by
Quadrupole Mass Spectrometry
Major collagen present in HYPERTROPHIC CARTILAGE
Type X
Major collagen in KELOID
Type 3 > Type 1
The structural proteins are involved in maintaining the shape of a cell or in the formation of matrices in the body. The shape of these protein is
FIBROUS
Quarter arrangement is seen jn
COLLAGEN
Type of collagen present in SKIN HEMIDESMOSOMES
Type XVII
Type of collagen present in RHABDOMYOSARCOMA
Type XIX
Type of collagen present in BRAIN
Type XXV
Type of collagen present in TESTIS AND OVARY
Type XXVI
Functions of Golgi Bodies
O-glycosylation of proteins
protein sorting
processing of oligosaccharide chains of glycoproteins
Prion Related Protein Diseases
Alzheimer Disease Parkinson's Disease Huntington's Disease Fronto Temporal Dementia Dementia with Lewy Bodies Amyloidosis Beta thalassemia
Which of the ff groups of proteins assist in the folding of other proteins?
a. Proteases
b. Proteosomes
c. Templates.
d. Chaperones
d. Chaperones
Chaperones
Belong to heat shock proteins
wide range of expression
present from bacteria to human
also known as STRESS PROTEINS
