BMB 251 1st Edition Lecture 12 Outline of Last Lecture I. Proteinsa. Binding sites b. Ligandc. AntibodiesII. Equilibrium constant (K)III. Enzyme CapabilitiesIV. LysozymeV. CoenzymesVI. Allosteric bindinga. Negative regulators/inhibitorsb. Positive regulators/cofactorsOutline of Current Lecture VII. Clicker QuestionsVIII. GTP/GDP moleculesIX. Protein p53X. Watson/Crick Model of DNAXI. Nucleotides and Base PairsCurrent Lecture- Clicker Question 1: What kinds of interactions DO NOT contribute to the formation of an enzyme-substrate complex?a) Covalentb) Ionic/electrostaticc) H-bondsd) Van der Waals/LDFe) All of the above contributeo Binding interactions are ALL noncovalent; you can have an allosteric regulator (still noncovalent); you can attach a PO4 group (which is covalently bound); but substrate-enzyme complex always binds noncovalently- Clicker question 2: Allosteric regulators that deactivate enzymes are called allosteric inhibitors and it’s called negative regulation- Clicker Question 3: Allosteric regulators that activate enzymes are called co-factors, and it’s called positive regulation- Cdk protein is only active as a serine/threonine protein kinase if it is bound to second protein called cyclin- Scr protein: first tyrosine kinase to be discovered (deregulation cause sarcoma tumor)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Ras protein: important role in cell signaling; in GTP-bound form, it’s active and stimulates lots of protein phosphorylations in cell; most of time, protein is inactiveo GDP-bound form becomes active when switching GDP for GTPo **Ras = inactivated by GTPase-activating protein (GAP) because it induces Ras to hydrolyze its bound GTP to GDP, but GEF reactivates it by releasing GDP- Allosteric proteins can also pump ions/molecules across membrane via the harnessing of energy from ATP hydrolysis, ion gradients or ETCo Ex. ABC transporters (membrane-bound pump proteins)- Protein p53: plays central part in controlling cell’s response to adverse circumstances; can be modified at 20 different sites (protein’s principle can be altered in a huge number of ways)- Hereditary info which is used to create and maintain a living organism is passed from cell to daughter cells via cellular division and from one generation to the next via the organism’s reproductive cells o Stored in all living organisms as genes (determine the characteristics of a species and theindividuals within it)- Protein functions: building blocks for cell structures, form enzymes to catalyze reactions, regulate gene expression, enable cells to communicate with one another, control most cellular movemento Properties/functions of cell = determined largely by the proteins it is able to create- 1953= James Watson and Francis Crick created theories for DNA structure (double helix) and replication process- Deoxyribonucleic acid (DNA): two long, unbranched polynucleotide chains with four different subunitso Backbone = sugars and PO4s, nucleotides are covalently bound togethero Nucleotides between two separate chains are linked via H-bondso DNA has subunits (nucleotides) that fit together and are placed in the same orientation one side a has a 5’ PO4 group and the other a 3’ OH- group; because of this, DNA is polar and has one 5’ PO4 terminal end and another 3’ OH terminus- Nucleotides are the monomers that polymerize to make DNA and RNA nucleic acidso Deoxyribose or ribose = 2’ Co 5’ and 3’ C linkages o Can have an alpha, beta and/or gamma PO4’s depends on how many PO4’s are presento The N-base is numbered with regular numberso The Carbon sugar is then numbered with prime numberso In DNA, the “deoxy” means the removal of one of the oxygens that are present in RNA; this O-atom is taken away and only an H-atom is bound to the C-atom- G-C pairs are stronger than A-T pairs because they have 3 H-bonds rather than 2 (like
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