-
If the pyrollidine ring of proline is reduced to a linear to a linear form, the new amino acid will have
(1) constrained ϕ than proline
(2) constrained Ψ than proline
(3) relaxed ϕ than proline
(4) unaffected ϕ and Ψ
Effect of Pyrrolidine Ring Reduction in Proline on ϕ and Ψ Angles
Proline is unique among amino acids due to its cyclic pyrrolidine ring, which significantly restricts the ϕ (phi) angle in protein structures. If this ring is reduced to a linear form, the amino acid will experience notable changes in its conformational flexibility.
Correct Answer:
The correct answer is:
(3) Relaxed ϕ than proline
Why Does the ϕ Angle Become More Relaxed?
- The pyrrolidine ring in proline locks the ϕ angle at around -60°.
- If the ring is reduced to a linear structure, this restriction is removed.
- This allows greater rotation around the N-Cα bond, leading to a more relaxed ϕ angle.
Impact of Pyrrolidine Ring Reduction
1. Increased Backbone Flexibility
- Proline’s rigid structure makes it ideal for turns but limits its use in α-helices and β-sheets.
- A linear form would increase flexibility, making it behave more like standard amino acids.
2. Effect on Secondary Structure Formation
- Proline prefers β-turns due to its constrained dihedral angles.
- The linear form would allow it to participate more easily in α-helices and β-sheets.
3. Ramachandran Plot Changes
- Proline is highly restricted in the Ramachandran plot, occupying a small region.
- A linearized proline would expand its allowable conformational space.
Biological and Structural Implications
1. Protein Folding & Stability
- Removing proline’s rigidity could destabilize structures that rely on its constrained angles.
- It may introduce greater conformational flexibility in protein folding.
2. Peptide Design & Engineering
- Synthetic modifications of proline are used in drug design to control protein flexibility and stability.
- Altering proline can influence protein-protein interactions.
Conclusion
If proline’s pyrrolidine ring is reduced to a linear form, the ϕ angle becomes more relaxed, increasing flexibility in protein structures. This alteration can significantly impact secondary structure formation, protein folding, and peptide stability.
32 Comments
Suman bhakar
March 27, 2025👍
Priyam choudhary
April 24, 2025Done
Aakansha sharma Sharma
September 25, 2025(3) relaxed ϕ than proline is correct
Soniya Shekhawat
September 25, 2025Relaxed phi than proline bcz ϕ angle becomes more relaxed due to less steric heridance in linear form
Kirti Agarwal
September 26, 2025Relaxed phi angle
Santosh Saini
September 26, 2025The phi angel becomes more relaxed and increasing flexibility in protein structure
Neha Yadav
September 26, 2025proline’s pyrrolidine ring is reduced to a linear form, the ϕ angle becomes more relaxed due to the less steric hindrance which allowed rotation around the N- C bond
Minal Sethi
September 26, 2025Relaxed ϕ than proline
Devika
September 26, 2025The Phi angle become more relaxed
sakshi vijay
September 26, 2025relaxed phi than proline b/c this ring makes proline rigid no free rotation in phi but linear chain of proline relaxed ( free rotation)in phi
Muskan Yadav
September 26, 2025Relaxed ϕ than proline.
Pallavi Ghangas
September 26, 2025relaxed phi then proline
Priti khandal
September 26, 2025Relaxed phi then proline
Priti khandal
September 27, 20253 is correct answer
Kavita Choudhary
September 27, 2025Relax phi then prolin beoz phi angel is more relax due to less stric hindirance and allowed rotion in N-C bond
Khushi Singh
September 27, 2025Due to less steric hindrance
Kajal
September 28, 2025Done
Manisha choudhary
September 28, 2025Due to pyrollidin ring in proline ,proline form beta turn
Phi angle ko -60° p block kr deta h ise linear krne s phi angle relax ho jayega proline helix and beta sheet bna skti h
Mohd juber Ali
September 28, 2025Proline is a regid structure and higly restricted
When phi bond is more rigid then less torsion and free rotation is possible
According to question when pyrolidin ring of proline is reduced to linear form then restricion removed new aa will have relaxed phi than proline due to form linear structure the flexibility of proline is increase
Arushi Saini
September 28, 2025proline’s pyrrolidine ring is reduced to a linear form, the ϕ angle becomes more relaxed
Mansukh Kapoor
September 28, 2025The correct answer is option 3rd
The phi angle becomes more relaxed
Sakshi Kanwar
September 28, 2025Pyrrolidine Ring is attached to N-C which forms the phi angle after becoming linear it relaxed the phi angle than proline
roopal sharma
September 28, 2025phi angle is relaxed and it can also participate in formation of helix and beta structure.
Avni
September 28, 2025If proline’s pyrrolidine ring is reduced to a linear form, the phi angle becomes more relaxed,
Anurag Giri
September 28, 2025Correct answer is 3
Proline is unique among amino acids due to its cyclic pyrrolidine ring, which significantly restricts the ϕ (phi) angle in protein structures. If this ring is reduced to a linear form, the amino acid will experience notable changes in its conformational flexibility
Heena Mahlawat
September 28, 2025Relaxed phi than proline
Divya rani
September 29, 2025Pyrrolidine ring in proline between N-C is make the pr online rigid so phi angle can not rotate so if it will become linear so phi angle will relaxed than proline.
Rishita
September 30, 2025Opt 3
Preeti sharma
October 1, 2025The phi angle become for relaxed
Pooja
October 5, 2025Option c is correct
relaxed ϕ than proline
Neeraj Sharma
October 5, 2025The correct answer is relaxed phi than proline because if the ring is reduced to linear then no more boundation on N-alphaC bond means phi will be relaxed
Priyanshi Sharma
October 6, 2025Relaxed phi than prolin