Structure of
DNA, RNA, and Protein
2
BLACKJACK3D/ISTOCKPHOTO
Contents 1 DNA structure
RNA structure
2
Protein structure
3
DNA Structure
DNA Structure
• Monomers are called nucleotides
(base + sugar + phosphate).• Sugar and phosphate form the backbone.
• Base = purine or pyrimidine
✔
Purines = adenine (A), guanine (G)
✔
Pyrimidines = thymine (T), cytosine (C).
• Held together by H-bonds between the bases.
(Weaver, 2002)
G C
T
A
Refer to the 3′ and 5′ ends of the DNA
Directionality of DNA
(Russel, 2010)
DNA Structure: A-, B- & Z-form DNA
DNA Functions
Carrying genetic information Controlling living cells activity
Synthesizing RNA Synthesizing Proteins
1 2
3 4
Contents
RNA structure
2
DNA structure
1
Protein structure
3
DNA RNA
Sugar Deoxyribose Ribose
Strand Double-stranded
molecule Single-stranded
molecule
N base Thymine bonds with
adenine Uracil Instead of thymine
Location Nuclear DNA never
leaves the nucleus
Assembled in nucleus, moves to cytoplasm (leaves the nucleus)
DNA vs RNA
DNA vs RNA
Uracyl and Ribose structure
RNA Types
carries the genetic information copied from DNA in the form of a series of three-base code “words,” each of which specifies a particular amino acid.
Messenger RNA (mRNA)
binds amino acid and carries it to the growing end of a polypeptide chain. each specific tRNA molecule contains a three-base sequence that can base-pair with its complementary code word in the mRNA
Transfer RNA (tRNA)
Has a role in protein synthesize (forming ribosomes)
.
Ribosome RNA (rRNA)
Pre-mRNA
Messenger RNA (mRNA)
mRNA
Ribosome RNA (rRNA)
Genetic codes
Contents
Protein structure
3
DNA structure
1
RNA structure
2
Why do we learn protein?
Function of Protein
18
Proteins – Some Basics
Linear Sequence of Amino Acids
What Is a Protein? What Is an Amino Acids?
determine the properties of
amino acids
Proteins – Some Basics
19
●
20 Naturally Occuring Amino Acids
●
Differ only in Side Chains (R) How many types of amino acids?
Isoleucine Tyrosine
Amino Acids connect via Peptide Bond
Primary:
Sequence of a chain of amino acid.
Quaternary structure occurs in multienzyme complexes.
Quaternary:
Protein consisting of more than one amino acid chain.
Tertiary:
Certain attractions are present between α helices and β sheets.
Secondary:
Sequence of amino acids are linked by H bond.
Levels of protein structure
Secondary:
Sequence of amino acids are linked by H bond.
Tertiary:
Certain attractions are present between α helices and β sheets.
Quaternary:
Protein consisting of more than one amino acid chain.
20 natural amino acids
Protein Folding and Disease
Tau protein stabilizes the microtubule that wraps every neuron.
Alzheimer’s disease
Tau protein is
hyperphosporylated, misfolded, then creates neurofibrillary tangles.
References
•
Nicholl. 2008. An Introduction to Genetic Engineering, Third Ediion. Cambridge.
•
Schleif R. Genetics and Molecular Biology, Second Edition. The Johns Hopkins University Press.
•
