1) You have isolated two proteins that you suspect are new actin capping factors
ID: 218958 • Letter: 1
Question
1) You have isolated two proteins that you suspect are new actin capping factors that may cap either the lus or minus ends of the filaments. To determine if this is the case and which end they cap,you measure ilament formation as a function of actin concentration in the presence and absence of "Protein 1' and Protein 2" (note, the X-axis is concentration, not time). Which protein caps the plus end and which caps he minus end? How can you tell? A) NO ADDED PROTEIN (B) PROTEIN 1 C) PROTEIN2 filament monomer filament monomer filament 0.2 04 0.6 0.8 actin concentration (uM) 0 0.2 0.4 0.6 0.8 actin concentration (uM) 0 0.2 0.4 06 0.8 actin concentration (uM)Explanation / Answer
Ans.
protein 1 caps the minus end of the filament as it has lowered the critical concentration of actin whereas protein 2 caps the plus end of the filament as it has increased the critical concentration of actin.
If the (-) end of an actin filament is capped, it can elongate only from its (+) end and plus end grows relatively fast resulting in a decrease in the critical concentration of actin.
If the (+) end of an actin filament is capped, it can elongate only from its (?) end and minus end grows slowly resulting in an increse in the critical concentration of actin.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.