Chapter 3 - Protein Structure and Function

A(n) ________ is synthesized by a complex process called translation.

The ________ kinase A exists in an "open "and "closed "conformation.

________ encoding a protein can be subjected to mutagenesis so that segments of the proteins backbone are removed or changed.

________ and peptides have been considered natural products of a cell.

________ are sometimes defined in functional terms on the basis of observations that an activity of a protein is localized to a small region along its length.

________ are referred to as polypeptides.

________ such as urea or guanidine hydrochloride at concentrations of 6- 8 M can disrupt the weak noncovalent interactions that stabilize the native conformation of a protein.

To protect a cell from degrading itself, endoproteases and ________ are synthesized and secreted as inactive forms (zymogens): pepsin by chief cells in the lining of the stomach; the others by pancreatic cells Alternatively Folded Proteins Are Implicated in Slowly Developing Diseases.

Include the ________ that encases the viral genome and bundles of cytoskeletal filaments that support and give shape to the plasma membrane.

The catalytic action of an enzyme on a given substrate can be described by two parameters: Vmax, the ________ of the reaction at saturating substrate concentrations, and Km (the Michaelis constant), a measure of the affinity of an enzyme for its substrate.

________ have systems that reduce the chances for misfolded proteins to form.

The ________ also makes use of the ubiquitin- mediated pathway in the response to altered self- cells, particularly virus- infected cells.

The ________ determines where transcription of a specific gene begins Members of Protein Families Have a Common Evolutionary Ancestor.

________ from heat, extremes of pH that alter the charges on amino acid side chains.

The ________ (polypeptide) is represented by daltons.

The ________ for protein degradation is the system of digestive proteases that breaks down ingested proteins into peptides and amino acids in the intestinal tract.

________ occurs in vitro, only a minority of unfolded molecules undergo complete folding into the native confirmation within a few minutes.

There are 20 ________ construed by polymerization into linear chains.

The ________ (EGF) domain is one example of a module that is present in several proteins.

________ have several intracellular proteolytic pathways for degrading misfolded or denatured proteins.

________ can be oriented in the same (parallel) or opposite (antiparallel) directions with respect to each other.

________ consist of Hsp70 and its homologs: Hsp70 in the cytosol and mitochondrial matrix, BiP in the endoplasmic reticulum, and DnaK in bacteria.

The ________ generated by the stator rotates an inner ring of proteins and the attached flagellum.

________ containing n residues could, in principle, fold into 8n conformations.

Interactions between the subunit and the ________ subunits directs the synthesis of ATP.

________ is a small, soluble peptide hormone that binds to cells in the embryo and in the skin and connective tissue in adults, causing them to divide.

________, protein self- splicing is an autocatalytic process, which proceeds by itself without the participation of enzymes Ubiquitin Marks Cytosolic Proteins for Degradation in Proteasomes.

________ refers to the overall conformation of a polypeptide chain- that is, the three- dimensional arrangement of all its amino acid residues.

The ________ to distinguish different molecules is perhaps most highly developed in the blood proteins called antibodies.

A protein is only able to function correctly when it is in its ________ or conformation.

________ is suppressed by two distinct mechanisms.

________ by Protein Kinases; after substrates have bound and the catalytic core of protein kinase A has assumed the closed conformation, the phosphorylation of a serine or threonine residue on the target peptide can take place Vmax and Km Characterize and Enzymatic Reaction.

The ________ is degradation by enzymes within lysosomes, membrane- limited organelles whose acidic interior is filled with hydrolytic enzymes.

A single polypeptide may exhibit multiple types of ________ depending on its sequence.

The overall helical structure is amphipathic Structural and ________ are Modules of Tertiary Structure.

________, domains can be recognized in structures determined by x- ray crystallography or in images captured by electron microscopy.

________ are also present in other proteins and are liberated by proteolysis.

________ refers to the ability of a protein to bind one molecule in preference to other molecules.

At the ________ and molecules, movement is affected by many different forces from those in the macroscopic world.

________ and RNA polymerases also are linear motor proteins because they translocate along with ________ during replication and transcription.

________ (working molecules of a cell) carry out a program of activities encoded by genes.

________ are thought to bind all nascent polypeptide chains as they are being synthesized on ribosomes.

Turns are composed of three or four residues, turns are located on the surface of a protein, forming sharp bends that redirect the polypeptide backbone back toward the interior Overall Folding of a(n) ________ Yields Its Tertiary Structure.

________ is primarily stabilized by hydrophobic interactions between the nonpolar side chains, hydrogen bonds between polar side chains, and peptide bonds.

________ that have a common ancestor are referred to as homologs.