Protein-X has a calcium (Ca²+)-binding regulatory subunit. Upon calcium (Ca²+) binding the protein changes its own conformation resulting in the conformation change of protein-Y. As a result of this calcium (Ca²+)-dependent protein-X mediated conformational change protein-Y exposes the myosin II head binding sites on the skeletal muscle actin filaments. Identify the protein-X and protein-Y from the following choices. O Protein-X: Troponin; Protein-Y: Tropomysosin O Protein-X: Tropomodulin; CapZ O Protein-X: Nebulin; Protein-Y: Titin Protein-X: Tropomysosin; Protein-Y: Tropomodulin

The hemoglobin in the fetus (HbF) is a structural variant of the hemoglobin in the mother (HbA). HbA is a tetrameric protein complex consisting of two α-globin and two β-globin subunits. HbF is made up of two αglobin and two γ-globin subunits, where the γ-globins are similar to the β-globins but γglobins have lower affinity for 2,3- bisphosphoglycerate or BPG. Studies of oxygen transport in pregnant mammals show that the oxygen-saturation curves between the red blood cells of the fetus and the mother are markedly different. 1. The shape of hemoglobin binding curves is: hyperbolic or sigmoidal 2. a) Based on the binding curves, determine the dissociation constant (Kd) for each hemoglobin complex. (Show correct units.) Kd of HbF + BPG: ________________ Kd of HbA + BPG: _____________________ b) Which has a higher affinity for oxygen? HbF+BPG HbA+BPG 3. a) How many BPG molecule(s) is/are expected to bind one hemoglobin complex? 1 2 3 4 b) BPG binding preferentially stabilizes which state…

Microfilaments are long filamentous proteins made up of many globular proteins. What main protein are microfilaments composed of?

It is not an easy matter to assign particular func-tions to specific components of the basal lamina, sincethe overall structure is a complicated composite materialwith both mechanical and signaling properties. Nidogen,for example, cross-links two central components of thebasal lamina by binding to the laminin γ-1 chain and totype IV collagen. Given such a key role, it was surprisingthat mice with a homozygous knockout of the gene fornidogen-1 were entirely healthy, with no abnormal phe-notype. Similarly, mice homozygous for a knockout of thegene for nidogen-2 also appeared completely normal. Bycontrast, mice that were homozygous for a defined muta-tion in the gene for laminin γ-1, which eliminated just thebinding site for nidogen, died at birth with severe defectsin lung and kidney formation. The mutant portion of thelaminin γ-1 chain is thought to have no other functionthan to bind nidogen, and does not affect laminin struc-ture or its ability to assemble into the basal lamina.…

When you think about the primary structure of the mannose-6-P receptor, assuming that it is an integral membrane protein with one membrane-spanning domain and assuming that it has a ERSS, what are all of the different protein domains that must be present in this protein's primary structure to get it to where it needs to go and to carry out all of the functions/activities? (Draw a schematic of the protein structure/sequence and explain each region). What do you think would happen to a soluble protein that normally contains a KDEL tag (ER retrieval) if the tag was cleaved off (where would the protein end up)?

The figure  from Moore (2020) shows a G protein-coupled receptor in a membrane. Note that "out" means outside the cell and "in" means facing the cytoplasm. The three amino acids "DRY" in loop I2 are required  for protein targeting. What is the name of this kind  of sequence, and what is its function? What protein targeting sequence is no longer included in this diagram? Why? The sequence "QXXNK" (where X is any amino acid) found in loop I3 has been identified based on its enzymatic activity. What is this activity? What particular domain would you expect to find in either Loop E1, E2, or E3?  The gene that codes for this protein is a member of  a family of genes that has arisen over evolutionary time. If you compared several of the genes in this family, would you expect their sequences to be most homologous (similar) in the region you describe in #3 above or #4 above? Why?

During elongation eEF1α complexed to GTP escorts the aminoacyl tRNA to the ribosome. True False

T/F Type I collagen fibers, that consist of collagen triple helices aligned side-by-side, are strengthened by covalent cross-links between amino acid side chains of different collagen triple helices. True O Failse

Given the effect of myosin heavy chain phosphorylation on myosin II assembly/disassembly, why might it make sense to find this kinase near the contractile ring as the process of cell division is concluding?

Most of the GLP-1 receptor structure form part of the transmembrane domain (TMD) that is embedded in the plasma membrane. The TMD enables the transmission of signal induced by the binding of GLP-1 from outside the cell into the cytoplasm of the cell, which in turn initiates a signaling cascade that ultimately leads to insulin secretion. Is the TMD of the receptor mainly hydrophobic or hydrophilic? Explain your answer in 1 – 3 sentences.