Protein Structures and their Role in Diseases
ASSESSMENT 1
Name: Ahmed Abdelnaby
ID: 20170030005
Course: BIO 112
Dr. Cijo Vazhappilly
20/04/2022
Contents
Introduction: ................................................................................................................................................. 3
Function of Proteins:..................................................................................................................................... 3
1.
Protein as Antibody:......................................................................................................................... 3
2.
Protein as Enzyme; ........................................................................................................................... 3
3.
Protein as Hormones:....................................................................................................................... 4
4.
Protein as Body Structure: ............................................................................................................... 4
5.
Protein as Carrier:............................................................................................................................. 4
Chemical Composition of Protein: ................................................................................................................ 4
Structures of Proteins: .................................................................................................................................. 5
1.Primary Structure of Protein: ................................................................................................................. 5
2.Secondary Structure of Protein: ............................................................................................................ 5
3.Tertiary Structure of Protein:................................................................................................................. 6
4.Quartenary Structure of Protein: ........................................................................................................... 7
Sickle Cell Anemia: ........................................................................................................................................ 7
Prion Disease (Jakob Disease): ...................................................................................................................... 8
Amyloidosis: .................................................................................................................................................. 9
Alzheimer's disease: ...................................................................................................................................... 9
Parkinson’s Disease:...................................................................................................................................... 9
Huntington's disease:.................................................................................................................................. 10
Other Diseases associated with structure of protein: ................................................................................ 10
Conclusion: .................................................................................................................................................. 10
References: ................................................................................................................................................. 11
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Figure 1: Chemical Composition of Protein .................................................................................................. 4
Figure 2:Secondary Structure of Protein ...................................................................................................... 6
Figure 3: Tertiary Structure of Protein .......................................................................................................... 6
Figure 4: Quaternary Structure of Protein .................................................................................................... 7
Figure 5: The haem chain at the 6th number, is replaced with a valine ...................................................... 8
2
Protein Structures and their Role in Diseases
Introduction:
Proteins are large, complex macromolecules that perform many vital functions in the human body.
They are necessary for the body's development, activity, and regulation, and they perform most of
their functions inside the cells. These complex molecules are made up of thousands of simple
fragments called amino acids, joined in vast bonds to form proteins. A protein comprises 20
different types of amino acids that can be combined. The amino acid positioning determines the 3dimensional appearance and structure of each protein. The sequence of genomes determines the
variations of three DNA essential components (nucleotides) that encode amino acids. Every
protein has its function. Some proteins act as enzymes that play an essential role in many chemical
reactions inside the body. These enzymatic proteins help form new molecules by reading the
genetic material stored in the DNA. ("Khan Academy", 2022).
Function of Proteins:
There are five primary functions of the protein.
1. Protein as Antibody:
An antibody is an essential component of the body’s immune system. Antibodies are made up
of proteins that help kill pathogens like bacteria and viruses—for example, immunoglobulins.
2. Protein as Enzyme:
Enzymes are proteins that act as a catalyst in promoting any biochemical reaction in the body—
for example, Pepsin promotes a reaction in the digestive system.
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3. Protein as Hormones:
Hormones are also made up of proteins secreted by different endocrine and exocrine glands in
the body. They regulate normal physiological processes happening in the body—for example,
thyroid hormone and growth hormones.
4. Protein as Body Structure:
Proteins also make up different body structures, such as hairs and nails—for example, Keratin.
5. Protein as Carrier:
Some proteins also act as carriers for different molecules throughout the body, such as
Ferritin. (Genetics & Work, 2022)
Chemical Composition of Protein:
Amino acids, which are specific chemical molecules comprised of an alpha (central) carbon atom
attached to an amino and carboxyl group, a hydrogen atom, and a varying constituent called the
side chain, are the building blocks of proteins (see below). Several amino acids within a protein
are cross-linked to form a long chain. To form peptide bonds, a biological basis eliminates a
water molecule by connecting the amino group of one amino acid to the carboxyl group of
neighbouring amino acids. The standard technique of amino acids that make up a protein is its
primary structure.
Figure 1: Chemical Composition of Protein
4
Structures of Proteins:
There are 4 basic structures of proteins which are as follows:
1.Primary Structure of Protein:
Underlying structure refers to the positioning of amino acids in a polypeptide string, which is the
main level of protein complexes. The structure of a protein is determined by the DNA of the
genome that causes it. A modification in the gene's DNA structure may shift the protein's amino
acid composition. A specific amino acid alteration in the structure of the protein can alter its entire
form and composition ("Khan Academy", 2022)
2.Secondary Structure of Protein:
Discrete folded patterns that emerge within a polypeptide as a series of contact between central
structural atoms are secondary structures. (R group atoms are absent from this structure because
the entire polypeptide chain is considered vital, not just the R groups.) The two most common
types of secondary structures are the alpha-helical and the beta-pleated sheet. The primary
distinction between the alpha and beta-helix is the sort of hydrogen bonding they exhibit. The
alpha helix exhibits intramolecular hydrogen bonding, whereas the beta-helix exhibits
intermolecular hydrogen bonding. (Berg, J. M., 2002)
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Figure 2:Secondary Structure of Protein
3.Tertiary Structure of Protein:
This formation of a protein is its general 3-D form. The protein will change its shape to obtain
the highest stabilization or most minor energy configuration possible. Even though the threedimensional form appears to be uneven and arbitrary, it is shaped by several stabilizing factors
resulting from bond formation between the amino acid side-chain groups. (Rehman, I 2017)
Figure 3: Tertiary Structure of Protein
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4.Quartenary Structure of Protein:
Several proteins are composed of a solitary polypeptide chain with only three tiers of the
organization. However, a few proteins are made up of several polypeptide chains, which are
referred to as subunits. Quaternary structures form when these subunits combine. Hemoglobin, for
example. Hemoglobin which carries oxygen in the blood, has four subunits, two each. The forces
that lead to tertiary structure (hydrogen bonding) also keep the components banded to create the
quaternary formation. ("Khan Academy", 2022)
Figure 4: Quaternary Structure of Protein
Sickle Cell Anemia:
This is a disease associated with the primary structure of the protein. Therefore, a specific amino
acid variation is connected to this disease. In this disease, red cells of the blood are affected. A
singular polypeptide chain constituting hemoglobin in sickle cell anemia has a slight structural
change. In this condition, glutamic acid, which is present in the haem chain at the 6th number, is
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replaced with a valine (1 of 2 kinds of chains making up hemoglobin).
Figure 5: The haem chain at the 6th number, is replaced with a valine
Hemoglobin is made up of 2 chains, each with 150 amino acids. The maximum number of amino
acids in this protein is six hundred. Surprisingly, only a change in 2 amino acids out of 600 leads
to this condition. The body of an individual with sickle cell anemia generates only sickle cell
hemoglobin. The amino acid change from glutamic acid to valine allows hemoglobin molecules
to arrange into continuous strands, resulting in these. Disc-shaped erythrocytes turning crescentshaped due to the fibers. These abnormal cells stuck have difficulty moving across blood vessels.
Difficulty breathing, vertigo, headaches, and stomach pain are all symptoms of entrapped cells are
signs of this condition. (Khan Academy, 2022)
Prion Disease (Jakob Disease):
This disease is related to eating of meat of an infected cow with bovine spongiform
encephalopathy. Disease occur due to mutation in the secondary structure of the protein. The
transition of standard cellular Prion protein from an alpha-helical framework to an illness version
with a beta pleated conformation, known as PrP scrapies, characterizes the pathogenesis of prion
diseases. (Mays, C. E., & Soto, C. 2016). The Beta- pleated form is not degradable and participates
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in a series that results in the transformation of regularly gathered prion protein into the pathologic
misfolded form. The pathogenic form induces neuronal and glial cell destruction, resulting in the
creation of intracellular vacuoles. (Vacca Jr, V. M. 2016).
Amyloidosis:
When a protein is unable to acquire—it’s physiological, functioning fold, amyloid deposition
develops. The ill-folded proteins subsequently form fibrils in the interstitial space by assembling
with others of its kind, in a highly organized way. Amyloid accumulation is linked to organ
dysfunction and results in a slew of clinical disorders affecting the heart, kidneys, and brain.
(Gillmore, J. D., 2013)
Alzheimer's disease:
It is due to buildup of beta-amyloid in the brain, which results in the production of amyloid plaques. The
genome for the Beta-amyloid progenitor molecule, which is situated on chromosome 21, is the source of
this. Initial Alzheimer's disease affects a substantial percentage of persons with Down syndrome, also
known as trisomy 21, or trisomy 21. (Reiss, A. B., 2018) Brain cells in this disease are affected and ability
to remember anything is lost by the person and even body is unable to do any simple task. ("What Is
Alzheimer's Disease?", 2022)
Parkinson’s Disease:
It is a series of disorders called "protein faulty folding diseases," since it is marked by the deformed
and dysfunctional of certain proteins. These proteins subsequently form fiber strands that are
poisonous to other cells. (University of Cambridge, 2016) Trembling, tightness, trouble moving,
balancing, and coordination are all symptoms. ("Parkinson's Disease", 2022)
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Huntington's disease:
A CAG trinucleotide repetition in the gene that encodes the related proteins protein causes
Huntington's disease, a delayed neurological illness. It's a, heredity disease. In this disease atrophy
of nerve cells occur. Ultimately it affects all the functions which are under control of nervous
system resulting in incoordination or abnormal movement and some phycological signs. (JimenezSanchez, M., 2017)
Other Diseases associated with structure of protein:

Type 2 diabetes

Inherited cataracts

Atherosclerosis

Hemodialysis (Reynaud, E. 2010)
Conclusion:
As discussed, earlier proteins are made up of amino acids and they make body immune system,
antibodies and act as enzymes or hormones which regulate different biochemical reactions in the
body. These functions show the importance of the proteins in maintenance of physiological nature
of the body. Any change in the sequence of any single amino acids will result in abnormal structure
of these proteins. This mutation could be pathogenic or mutagenic and will lead to severe genetic
disorder which are not easily treatable.
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References:

Genetics, H., & Work, H. (2022). What are proteins and what do they do?: MedlinePlus
Genetics. Medlineplus.gov. Retrieved 8 April 2022, from
https://medlineplus.gov/genetics/understanding/howgeneswork/protein/#:~:text=Proteins
%20are%20large%2C%20complex%20molecules,the%20body's%20tissues%20and%20
organs.

Protein structure: Primary, secondary, tertiary & quatrenary (article) | Khan Academy.
Khan Academy. (2022). Retrieved 10 April 2022, from
https://www.khanacademy.org/science/biology/macromolecules/proteins-and-aminoacids/a/orders-of-protein-structure.

Berg, J. M., Tymoczko, J. L., and Stryer, L. (2002). Secondary structure: Polypeptide
chains can fold into regular structures such as the alpha helix, the beta sheet, and turns
and loops. In Biochemistry (5th ed., section 3.3). New York, NY: W. H. Freeman.
Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK22580/.

Rehman, I., Kerndt, C. C., & Botelho, S. (2017). Biochemistry, Tertiary Protein
Structure.

Gillmore, J. D., & Hawkins, P. N. (2013). Pathophysiology and treatment of systemic
amyloidosis. Nature Reviews Nephrology, 9(10), 574-586.

Vacca Jr, V. M. (2016). CJD: Understanding Creutzfeldt-Jakob disease. Nursing2020,
46(3), 36-42.

Mays, C. E., & Soto, C. (2016). The stress of prion disease. Brain research, 1648, 553560.

Reiss, A. B., Arain, H. A., Stecker, M. M., Siegart, N. M., & Kasselman, L. J. (2018).
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
Amyloid toxicity in Alzheimer’s disease. Reviews in the Neurosciences, 29(6), 613-627.

What Is Alzheimer's Disease?. National Institute on Aging. (2022). Retrieved 10 April
2022, from https://www.nia.nih.gov/health/what-alzheimersdisease#:~:text=Alzheimer's%20disease%20is%20a%20brain,appear%20in%20their%20
mid%2D60s.

University of Cambridge. (2016, September 19). Parkinson's disease protein plays vital
'marshalling' role in healthy brains. ScienceDaily. Retrieved April 9, 2022 from
www.sciencedaily.com/releases/2016/09/160919084606.htm

Parkinson's Disease. National Institute on Aging. (2022). Retrieved 10 April 2022, from
https://www.nia.nih.gov/health/parkinsons-disease.

Jimenez-Sanchez, M., Licitra, F., Underwood, B. R., & Rubinsztein, D. C. (2017).
Huntington’s disease: mechanisms of pathogenesis and therapeutic strategies. Cold
Spring Harbor perspectives in medicine, 7(7), a024240.

Reynaud, E. (2010) Protein Misfolding and Degenerative Diseases. Nature
Education 3(9):28
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