Post on 02-Jan-2016
Introduction to Bioinformatics
Yana Kortsarts
References: An Introduction to Bioinformatics Algorithms
bioalgorithms.info
What is Bioinformatics? Bioinformatics is a relatively new
interdisciplinary field that integrates computer science, mathematics, biology, and information technology to manage, analyze, and understand biological, biochemical and biophysical information.
Bioinformatics is a computational science and the subset of larger field of Computational Biology.
What is Bioinformatics? Bioinformatics is the use of computers to study
biology Bioinformatics is the science of using
information to understand biology Bioinformatics is integration of information
technology (IT) and biology Bioinformatics is the development of
computational methods for studying structure, function and evolution of genes, proteins and whole genomes
Course Curriculum Ethics, Computing and Genomics Review of Molecular Biology and
Biochemistry Concepts DNA and protein structure Gene expression (transcription and translation) Molecular Biology Central Dogma
Biological Research on the Web Public Biological Databases and Data Formats Searching Biological Databases
Course Curriculum Introduction to Bioinformatics Algorithms
Sequence alignments, scoring, gaps Algorithm Design Techniques: Exhaustive Search,
Dynamic Programming The Needleman and Wunsch Algorithm The Smith-Waterman Algorithm Introduction to BLAST Multiple Sequence Alignment Phylogenetic Trees
Introduction to Python and Biopython in UNIX environment
Some Terminology Cell is a primary unit of life Cell consists of molecules, chemical
reactions and a copy of the genome for that organism
All life on this planet depends on three types of molecules: DNA, RNA and proteins
Some Terminology DNA
Holds information on how cell works RNA
Acts to transfer short pieces of information to different parts of cell
Provide templates to synthesize into protein Proteins
Form enzymes that send signals to other cells and regulate gene activity
Form body’s major components (e.g. hair, skin, etc.)
DNA - Deoxyribonucleic Acid Genetic material
Consists of two long strands Each strand is made of:
Phosphates Sugar Nucleotides
A (adenine) G (guanine) C ( cytosine) T (thymine)
DNA – Double Helix Structure
Discovery of DNA DNA Sequences
Chargaff and Vischer, 1949 DNA consisting of A, T, G, C
Adenine, Guanine, Cytosine, Thymine Chargaff Rule
Noticing #A#T and #G#C A “strange but possibly meaningless”
phenomenon. Wow!! A Double Helix
Watson and Crick, Nature, April 25, 1953
Rich, 1973 Structural biologist at MIT. DNA’s structure in atomic resolution. Crick Watson
1 Biologist1 Physics Ph.D. Student900 wordsNobel Prize
Watson & Crick – “…the secret of life”
Watson: a zoologist, Crick: a physicist
“In 1947 Crick knew no biology and practically no organic chemistry or crystallography..” – www.nobel.se
Applying Chagraff’s rules and the X-ray image from Rosalind Franklin, they constructed a “tinkertoy” model showing the double helix
Their 1953 Nature paper: “It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material.”
Watson & Crick with DNA model
Rosalind Franklin with X-ray image of DNA
DNA: The Basis of Life Deoxyribonucleic Acid (DNA)
Double stranded with complementary strands A-T, C-G DNA is a polymer
Sugar-Phosphate-Base Bases held together by H bonding to the opposite strand
DNA, continued
Phosphate
Base (A,T, C or G)
http://www.bio.miami.edu/dana/104/DNA2.jpg
Sugar
DNA, continued DNA has a double helix structure. However,
it is not symmetric. It has a “forward” and “backward” direction. The ends are labeled 5’ and 3’ after the Carbon atoms in the sugar component.
5’ AATCGCAAT 3’
3’ TTAGCGTTA 5’
DNA always reads 5’ to 3’ for transcription replication
Double helix of DNA
The Central Dogma of Molecular Biology
Information has been transferred from DNA (information storage molecule) to RNA (information transfer molecule) to a specific protein (a functional, non-coding product)
DNA RNA Protein
transcription translation
DNA, RNA, and the Flow of Information
TranslationTranscription
Replication
Central Dogma (DNARNAprotein)
The paradigm that DNA directs its transcription to RNA, which is then translated into a protein.
Transcription(DNARNA) The process which transfers genetic information from the DNA to the RNA.
Translation(RNAprotein) The process of transforming RNA to protein as specified by the genetic code.
RNA RNA is similar to DNA chemically. It is usually only
a single strand. T(hyamine) is replaced by U(racil) Some forms of RNA can form secondary structures
by “pairing up” with itself. This can have change its
properties dramatically.
DNA and RNA
can pair with
each other.
http://www.cgl.ucsf.edu/home/glasfeld/tutorial/trna/trna.giftRNA linear and 3D view:
More Terminology
Transcription of DNA DNA transcribed into RNA RNA exits as a single-strand unit and as a double-helix
as well RNA consist of A, C, G and U (uracil)
Types of RNA Messenger RNA – mRNA Transfer RNA – tRNA Ribosomal RNA – rRNA
More Terminology Translation of Messenger RNA (mRNA):
mRNA is translated into protein Proteins:
linear polymers built from amino acids The transfer of information from DNA to specific
protein via RNA takes place according to the genetic code. The RNA sequence is divided into blocks of three
letters This block is called CODON Each codon corresponds to the specific amino acid
More Terminology Four different nucleotides are used to build DNA
and RNA molecules – A, G, C, T and A, G, C, U 20 different amino acids are used in protein
synthesis Four nucleotides can be arranged in 64 different
combinations of three. There are 64 = 4*4*4 different codons Some codons are redundant and some have
special function – to terminate the translation process
Translation
The process of going from RNA to polypeptide.
Three base pairs of RNA (called a codon) correspond to one amino acid based on a fixed table.
Always starts with Methionine and ends with a stop codon
Cell Information: Instruction book of Life DNA, RNA, and
Proteins are examples of strings written in either the four-letter nucleotide of DNA and RNA (A C G T/U)
or the twenty-letter amino acid of proteins. Each amino acid is coded by 3 nucleotides called codon. (Leu, Arg, Met, etc.)
Protein Synthesis: Summary
There are twenty amino acids, each coded by three- base-sequences in DNA, called “codons” This code is degenerate
The central dogma describes how proteins derive from DNA DNA mRNA (splicing?)
protein The protein adopts a 3D
structure specific to it’s amino acid arrangement and function
Proteins
Complex organic molecules made up of amino acid subunits
20 different kinds of amino acids. Each has a 1 and 3 letter abbreviation.
http://www.ncbi.nlm.nih.gov/Class/MLACourse/Modules/MolBioReview/iupac_aa_abbreviations.html
Proteins are often enzymes that catalyze reactions. Also called “poly-peptides”
*Some other amino acids exist but not in humans.