Concept explainers
RIPs as Cancer Drugs Researchers are taking a page from the structure-function relationship of RIPs in their quest for cancer treatments. The most toxic RIPs, remember, have one domain that interferes with ribosomes, and another that carries them into cells. Melissa Cheung and her colleagues incorporated a peptide that binds to skin cancer cells into the enzymatic part of an RIP, the E. coli Shiga-like toxin. The researchers created a new RIP that specifically kills skin cancer cells, which are notoriously resistant to established therapies. Some of their results are shown in FIGURE 9.17.
FIGURE 9.17 Effect of an engineered RIP on cancer cells. The model on the left shows the enzyme portion of E. coli Shiga-like toxin engineered to carry a small sequence of amino acids (in blue) that targets skin cancer cells. (Red indicates the active site.) The graph on the right shows the effect of this engineered RIP on human cancer cells of the skin (); breast () liver (); and prostate ().
Why are some of the data points linked by curved lines?
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Biology: The Unity and Diversity of Life (MindTap Course List)
- eading list Cells have oligosaccharides displayed on their cell surface that are important for cell-cell recognition. Your friend has discovered a transmembrane glycoprotein, GP1, on a pathogenic fungal cell that is recognized by human immune cells. He decides to purify large amounts of GP1 by expressing it in bacteria. To his purified protein he then adds a branched 14-sugar oligosaccharide to the asparagine of the only Asn-X- Ser sequence found on GP1. Unfortunately, immune cells do not seem to recognize this synthesized glycoprotein. What's a likely explanation for this problem? O The oligosaccharide needs to be further modified before it's mature. O The oligosaccharide should've been added one sugar at a time. O The oligosaccharide needs a disulfide bond. O The oligosaccharideehould've been added to the serine instead of the asparagine.arrow_forwardThe steroid progesterone has an important role in the female reproductive system. Researchers interested in studying membrane progestin receptors (MPRS) developed a method to produce and purify the protein in active form. First, the researchers devised a way to prepare a specific MPR known as hMPRA using the machinery of yeast cells. In order to facilitate purification and identification in later studies, they manipulated the yeast cells so that they attached two different tags to the C-terminal end of the protein. The first tag, Compound 1, is a peptide sequence that acts as an epitope, part of a much larger peptide sequence that is recognized by the immune system. The second sequence consisted of six consecutive histidine residues (His). This sequence binds tightly to Ni2+ cations. In chromatography, (His), tag labeled proteins can be eluted from Ni²+. supported columns by adding a small molecule to the eluent that mimics the side chain of histidine.…arrow_forwardOnce the chains of peptides that make up lysyl-tRNA synthetase protein are synthesized in ribosomes, lysyl-tRNA synthetase needs to have the proper active site in order to perform its function, explain the process of protein folding necessary to have a proper 3-D structure, include effect of thermodynamics and different states in folding, including what happen when there are prolines that form peptide bonds with other amino acids, and any disulfide bridgesarrow_forward
- The steroid progesterone has an important role in the female reproductive system. Researchers interested in studying membrane progestin receptors (MPRs) developed a method to produce and purify the protein in active form. First, the researchers devised a way to prepare a specific MPR known as hMPRA using the machinery of yeast cells. In order to facilitate purification and identification in later studies, they manipulated the yeast cells so that they attached two different tags to the C-terminal end of the protein. The first tag, Compound 1, is a peptide sequence that acts as an epitope, part of a much larger peptide sequence that is recognized by the immune system. The second sequence consisted of six consecutive histidine residues (His). This sequence binds tightly to Ni2+ cations. In chromatography, (His), tag labeled proteins can be eluted from Ni²+- supported columns by adding a small molecule to the eluent that mimics the side chain of histidine. After preparing hMPRA, the…arrow_forwardWhich of the following would be a good chemotherapy approach: blocking formationof the ribonucleotide GTP or blocking formation of the deoxyribonucleotide dGTP?Why? Please explain the chemical differences between each of the two nucleotides. Use the specific processes below to support your choice by explaining how either GTP or dGTPare related to these and how loss of the particular molecule would affect each process. *PEP carboxykinase in gluconeogenesis*Succinyl-CoA synthetase in the TCA Cycle*Glucagon signal transductionarrow_forwardWhat enzyme catalyzes protein synthesis in bacteria? You discover a new broad-spectrum antibiotic that inhibits protein synthesis and named it Compound J. You want to determine the mechanism of action of Compound J. After treating bacteria cells with Compound J, you observe many ribosomes with long polypeptide chains bound to them. Based on this observation, make a hypothesis about which part of the ribosome Compound J is binding and how this specifically affects translation. What evidence supports that proper protein folding is essential to all domains of life? Name and describe the function/s of two specific molecules that help proteins fold in bacteria.arrow_forward
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- Only answer please, no need to explain… Thank you for your time. i: Modification of the 5 prime ends of eukaryotic mRNA is called? a) Capping b) Polyadenylation c) Splicing d) Transcription ii: Genetic Code is? a) The sequence of Nitrogenous Bases in mRNA that codes for a protein b) Is a Triplet Code c) is Non-Overlapping d) All of these iii. The process of formation of RNA is known as a) Replication b) DNA repair c) Translation d) Transcription iv. Which of the following statement is NOT true regarding transcription/RNA synthesis? a) RNA synthesis occurs in the nucleus b) Unlike DNA synthesis, the only selective sequence of DNA is transcribed to RNA c) RNA synthesis requires a short stretch of RNA primers d) DNA sequences, specific proteins, and small RNAs regulate RNA synthesisarrow_forwardA group of researchers isolate 'Protein X' from the wall of a human stomach with the intent of learning how to synthesize stomach tissue in the lab. Subsequently, they determine the exact sequence of amino acids of the protein in its unfolded state, and create a functional mRNA template to translate Protein X in vitro. They manage to translate an exact copy of the polypeptide chain in the lab, but then realize that it takes several days for the protein to fold into its final tertiary structure. In vivo, they observe that several thousand copies of Protein X are folded from polypeptide chains every minute. What is NOT a plausible explanation for this difference in folding times? The in vitro study lacks a key enzyme The temperature in vitro is too low The in vitro study lacks a key tRNA molecule The pH in vitro is too higharrow_forwardWhat molecular biology strategy can best be used to determine Failure of t-RNA to bind at the A site of the small subunit of the ribosome? Explain.arrow_forward
- Biology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781305073951Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage Learning