Global Approaches for Studying Protein-Protein Interactions

This quiz contains multiple-choice problems on protein and domain interactions, gene order, use and phylogeny to predict proteins.

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There exist three types of interactions between domains. Which of the following is not one of them?

Stable complex

Transient interaction

Multi-domain protein

Unstable interaction

Stable complexes consist of proteins that are __ associated with each other, like many __ proteins.

temporarily, oligomeric

temporarily, monomeric

permanently, oligomeric

permanently, monomeric

Sets of proteins that are part of stable complexes and sets of proteins involved in transient interactions __ in terms of gene expression similarity among the set of proteins.

Are similar


Are the same

Show similar function

The correlation of gene expression for pairs of transiently interacting proteins is __ compared to randomly chosen pairs of proteins.

Not significant

Only marginally significant

Totally significant

Significant to much extent

Membership in a stable complex differs from transient interaction in terms of evolutionary constraints upon sequence divergence. True or false?



The average sequence identity for proteins in stable complexes is 46%, whilst it is 41% for proteins in transient interactions. True or false?



Interactions between proteins can be computationally predicted by looking for sets of genes that occur as a

Single gene in at least one genome

Multiple genes in at least one genome

Multiple genes in various genomes

Single gene in various genomes

Genes that are consistently part of the same operon across different, distantly related genomes are likely to be part of the same protein complex or functional process across all species. True or false?



The conservation of gene order due to operon structure is __, so interactions of proteins specific to eukaryotes cannot be detected by gene order conservation.

Not applicable to archaea genomes

Not applicable to prokaryote genomes

Applicable to eukaryote genomes

Not applicable to eukaryote genomes

An approach for predicting __ to look for cases across a set of genomes where __ are part of the same gene in one genome resulted in the gene fusion method.

gene interactions, only three to four orthologs

gene interactions, two orthologs

protein interactions, two or more orthologs

protein interactions, two orthologs

Domains that are part of a multidomain protein are

Neither co-regulated nor colocalized

Not co-regulated but colocalized

Co-regulated and but not colocalized

Co-regulated and colocalized

The most detailed experimental information about protein-protein interactions comes from three-dimensional structures. True or false?



Physical contact between domains is crucial for cellular machinery functioning. True or false?



Which of the following statements is incorrect regarding yeast-two-hybrid screens?

The yeast-two-hybrid system uses the transcription of a reporter gene driven by the Gal4 transcription factor to monitor whether or not two proteins are interacting

The DNA-binding domain chimeric protein will not bind upstream of the reporter gene

If the activation domain chimeric protein interacts with the DNA-binding domain chimeric protein, the reporter gene will be transcribed

Disadvantages of the method are that only pairwise interactions are tested, and not interactions that can only take place when multiple proteins come together, as well as a high false positive rate

Which of the following statements is incorrect regarding the purification of protein complexes followed by mass spectrometry?

Isolating protein complexes from cells allows identification of interactions between ensembles of proteins instead of just pairs

Systematic purification of complexes on a large scale is done by tagging hundreds of genes with an epitope

Unlike in the yeast-two-hybrid assay, this does not involve chimeric genes

Affinity purification based on the epitope will then extract all the proteins attached to the bait protein from cell lysates

Quiz/Test Summary
Title: Global Approaches for Studying Protein-Protein Interactions
Questions: 15
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