1. From gene to protein Premedical biology

2. RNA  chemically similar to DNA, except it contains ribose instead of deoxyribose and has uracil instead of thymin  RNA molecule genes (eukaryotic) are thousands nucleotides long  almost always consist of a single strand  less stable

3. RNA  some molecules are able to self-replicate  mistakes in replication – variability = differentiation of RNA  family of closely related RNA sequencies  some molecules are able to self-catalysate

4. First genes were RNA molecules that polymerized abiotically and replicated themselves autocatalytically

5. Ribosyms  auto-replicating activity  RNA molecules with enzymatic activity (ribosome, spliceosome) Coenzymes  non-protein components in enzymes  many of them are derived from nucleotides  some coenzymes are ribonucleotids, rRNA, mRNA

8. Transcription Synthesis of RNA under the direction of DNA Information is simply copied from one to another according to complementarity of bases enzyme RNA polymerase the beginning = promotor and initial code transcription factors, terminator

10. Promotor Typical promoter region for a protein-coding eukaryotic gene.

11. the template strand is used as a template for RNA synthesis The transcript is pre-mRNA primary transcript (eukaryotic cells) 7methyl Guanosin cap is added immediately to 5‘ end for protection from degradation by hydrolytic enzymes and „attach“ sign for ribosomes poly(A) tail - polyadenylation of 3‘ end inhibit degradation of the RNA RNA processing

12. exons = encoding parts introns = non-encoding parts cutted out cut and paste job = splicing during the RNA processing is created messenger RNA – mRNA snRNPs = spliceosome Regulation

13. Genetic code nucleotide triplets specify amino acids 4 nucleotides specify 20 amino acids triplet code – three nucleotide according to base-pairing rules the mRNA base triplets are called codons shared by the simplest bacteria after the most complex plants and animals

14. genetic code is almost universal the genetic code must have evolved very early in the history of life In bacteria is transcription and translation coupled at the same time translation of eukarytes occurs in cytoplazm

15. Each codon along mRNA specifies which one of the 20 amino acids will be incorporated AUG for methionin and it is Initial codon termination codons: UAG, UGA, UAA (stop signals)

16. 61 of 64 triplets code for 20 amino acids There is redundancy, and it is not random codon of the same amino acids differ in third base of triplet one tRNA exist for each mRNA codon, but number of tRNA is 45, some tRNA have anticodons, that can recognize two or more different codons. correct a reading frame

17. tRNA mRNA – series of codons Interpreter is transfer RNA – tRNA transfer amino acid to a ribosome nucleotide triplet called anticodon (in tRNA) links a particular mRNA codon

18. amino acid is added to the growing end of a polypeptide chain in ribosome amino acid is joined to tRNA by specific enzyme aminoacyl- tRNA synthetase - 20 these enzymes L-shape of tRNA three-dimensional structure

19. Aminoacyl tRNA- synthetase joins a specific amino acids to a tRNA - covalent attachment of amino acids to its tRNA - hydrolysis of ATP

20. Ribosomes facilitate specific coupling of tRNA anticodons with mRNA codons subunits: proteins and ribosomal RNA made in nucleolus (eu)

21. Translation Initiation, elongation, termination specific fators, GTP Peptide bond – new amino acid and carboxyl end Iniciation factors, Elongation factors Termination

22. Polyribosomes Polyribosomes (or polysomes) are a cluster of ribosomes, bound to a mRNA molecule, read one strand of mRNA simultaneously.

23. Coupled transciption and translation in bacteria

24. Comparing protein synthesis in prokaryotes and eukaryotes very similar but with certain differencies different polymerases, euk. depends on transcription factors ribosomes are different – simultaneously transcribe and translate the same gene and protein can quickly diffuse nuclear envelope segregates transcription and translation processing stages provides ways to regulate and coordinate proteosynthesis and gene expression in the eukaryotic cells

25. From polypeptide to functional protein Coiling and folding are spontaneous actions Genes determines the primary structure, the primary structure determines conformation Chaperones Posttranslational modifications: certain amino acid are modified by attachment of sugars, lipids, phosphate groups…………….. Two or more polypeptides may join to become the subunits of a protein

26. Primary structure: the amino acid sequence Secondary structure: local structures stabilized by hydrogen bonds. The most common examples are the alpha helix, beta sheet and turns. Tertiary structure: the overall shape of a single protein molecule; most commonly the formation of a hydrophobic core, but also through salt bridges, hydrogen bonds, disulfide bonds. The tertiary structure is what controls the basic function of the protein. - as synonymous with the term fold Quaternary structure: the structure formed by several protein molecules (polypeptide chains), usually called protein subunits in this context, which function as a single protein complex. Protein structures

27. 3-dimensional structures of protein

28. Thank you for your attention Campbell, Neil A., Reece, Jane B., Cain Michael L., Jackson, Robert B., Minorsky, Peter V., Biology, Benjamin-Cummings Publishing Company, 1996 –2010.