#Question id: 885
#Unit 1. Molecules and their Interaction Relevant to Biology
The half-lives of many cytoplasmic proteins vary with the identities of their N-terminal residues via the N-end rule.
a) Proteins with the “destabilizing” N-terminal residues contain Asp, Arg, Leu, Lys, and Phe with their half-lives > 2 to 3 hours
b) Proteins with the “destabilizing” N-terminal residues with their half-lives of only 2 to 3 minutes contain; Asp, Arg, Leu, Lys, and Phe
c) Proteins contain Ala, Gly, Met, Ser, Thr, and Val have half-lives of >10 hours are stabilizing N-terminal residue in prokaryotes
d) Those with the “stabilizing” N-terminal residues Ala, Gly, Met, Ser, Thr, and Val have half-lives of >20 hours in eukaryotes
Which of the following is correct?
#Question id: 884
#Unit 1. Molecules and their Interaction Relevant to Biology
The hydrogen bonds, which are central features of protein structures, then what is the reason behind it makes only minor contributions to protein stability?
#Question id: 883
#Unit 1. Molecules and their Interaction Relevant to Biology
The “core autophagy machinery” controls the initiation and growth of the autophagosome and has been divided into three main protein groups:
i. A-ATG9, B-TOR, C-PI(3) Complex
ii. A- ATG9, B-PI(3) Complex, C-TOR
iii. The TOR kinase complex acts as a negative regulator of autophagy
iv. The TOR kinase complex acts as a positive regulator of autophagy
#Question id: 882
#Unit 1. Molecules and their Interaction Relevant to Biology
Choose correct statements about thermophilic proteins
I. The proteins found in thermophilic species are much more stable than their mesophilic counterparts.
II. All thermostable proteins have such a high incidence of salt bridges
III. the most important of which are an increased size of the protein’s hydrophobic core, an increased size of the interface between its domains and/or subunits, and a more tightly packed core as evidenced by a reduced surface-to-volume ratio.
IV. Several of these thermostable enzymes have a superabundance of salt bridges on their surfaces.
#Question id: 881
#Unit 1. Molecules and their Interaction Relevant to Biology
______and ________ are the first chaperones a newly made prokaryotic protein encounters. Subsequently, many partially folded proteins are handed off to other chaperones to complete the folding process. E. coli can tolerate the elimination of_______ or________, but not both, thereby indicating that they are functionally redundant.
#Question id: 880
#Unit 1. Molecules and their Interaction Relevant to Biology
The classic work of Christian Anfinsen in the 1950s on the enzyme ribonuclease revealed the relation between the amino acid sequence of a protein and its conformation. Ribonuclease is a single polypeptide chain consisting of 124 amino acid residues cross-linked by four disulfide bonds. Anfinsen’s plan was to destroy the three-dimensional structure of the enzyme and to then determine what conditions were required to restore the structure.
The critical observation of Anfinsen that the denatured ribonuclease, freed of urea and b -mercaptoethanol by dialysis;
I. The sulfhydryl groups of the denatured enzyme became reduced by air, and the enzyme spontaneously refolded into a catalytically active form.
II. These experiments showed that the information needed to specify the catalytically active structure of ribonuclease is contained in its amino acid sequence.
III. The 105 wrong pairings have been picturesquely termed “scrambled” ribonuclease.
IV. He found that scrambled ribonuclease spontaneously converted into fully active, native ribonuclease when trace amounts of b -mercaptoethanol were added to an aqueous solution of the protein.
Choose incorrect options;