nucleic acid structure - virginia tech

Nucleic Acid Structure

GBCB 5874: Problem Solving in GBCB

The Central Dogma

Nucleic Acids are Linear Polymers

Berg, J.M. et al. (2002) Biochemistry, Fifth Edition, W.H. Freeman and Co.

The Bases of Nucleic Acids

Berg, J.M. et al. (2002) Biochemistry, Fifth Edition, W.H. Freeman and Co.

The Sugars of Nucleic Acids

Berg, J.M. et al. (2002) Biochemistry, Fifth Edition, W.H. Freeman and Co.

Berg, J.M. et al. (2002) Biochemistry, Fifth Edition, W.H. Freeman and Co.

Backbones of DNA and RNA

Berg, J.M. et al. (2002) Biochemistry, Fifth Edition, W.H. Freeman and Co.

Nucleoside Terminology

ThymidineUridine

DeoxycytidineCytidine

DeoxyguanosineGuanosine

DeoxyadenosineAdenosineDNARNA

Nucleoside: base bonded to sugar

β-glycosidic linkage to N-9 of a purine base or N-1 of a pyrimidine base

Nucleotide Terminology

Thymidine…phosphate(Thymidylic acid)

Uridine…phosphate(Uridylic acid)

Deoxycytidine…phosphate(Deoxycytidylic acid)

Cytidine…phosphate(Cytidylic acid)

Deoxyguanosine…phosphate(Deoxyguanylic acid)

Guanosine…phosphate(Guanylic acid)

Deoxyadenosine…phosphate(Deoxyadenylic acid)

Adenosine…phosphate(Adenylic acid)

DNARNA

Nucleotide: nucleoside joined to one or morephosphate groups by an ester linkage

Bonded to C-5’ hydroxyl group ->nucleoside 5’-phosphate or 5’-nucleotide

Example of Nucleotide

DNA Double HelixBackbones in darker blue and red.Bases in lighter blue and pink.

Berg, J.M. et al. (2002) Biochemistry, Fifth Edition, W.H. Freeman and Co.

Watson-Crick Base Pairing

Berg, J.M. et al. (2002) Biochemistry, Fifth Edition, W.H. Freeman and Co.

Forms of DNA

DNA Backbone Parameters

DNA Grooves

Berg, J.M. et al. (2002) Biochemistry, Fifth Edition, W.H. Freeman and Co.

DNA Packing

Types of RNA

• mRNA (messenger RNA)– Template for protein synthesis (translation)

• tRNA (transfer RNA)– Carries activated amino acids to ribosome for

protein synthesis– At least one kind of tRNA for each of the 20 amino

acids• rRNA (ribosomal RNA)

– Major component of ribosomes

Structure of tRNA