-
The area of allowed regions in the Ramachandran map will be least for
(1) Gly
(2) L—Ala
(3) L-Pro
(4) α-methyl L-Valine
Which Amino Acid Has the Least Allowed Region in the Ramachandran Map?
The Ramachandran plot is a graphical representation of the allowed dihedral angles (ϕ and ψ) for amino acids in a polypeptide chain. The size of the allowed region varies based on the steric hindrance imposed by the side chain.
Correct Answer:
The correct answer is:
(4) α-Methyl L-Valine
Why Does α-Methyl L-Valine Have the Least Allowed Region?
α-Methyl L-Valine has a bulky α-methyl (-CH₃) group attached to the α-carbon, further increasing steric hindrance. This restricts its flexibility more than other amino acids, limiting its allowable phi (ϕ) and psi (ψ) angles.
Comparison of Allowed Regions in the Ramachandran Plot
1. Glycine (Gly) – Most Allowed Region
- Smallest side chain (-H), highest flexibility.
- Appears in multiple regions of the Ramachandran plot.
- Found in turns and flexible loops of proteins.
2. L-Alanine (L-Ala) – Moderately Allowed Region
- Contains a methyl (-CH₃) group, which provides some steric hindrance.
- Occupies α-helix and β-sheet regions but is still relatively flexible.
3. L-Proline (L-Pro) – Highly Restricted Region
- Has a cyclic side chain that locks its phi (ϕ) angle at ~-60°.
- Found mainly in β-turns and collagen structures.
4. α-Methyl L-Valine – Least Allowed Region
- Bulky α-methyl (-CH₃) group increases steric clash.
- Extremely limited phi (ϕ) and psi (ψ) flexibility.
- Least tolerated in α-helices and β-sheets.
Impact on Protein Structure
1. Protein Folding and Stability
- Flexible amino acids like glycine enable tight turns.
- Bulky amino acids like α-methyl L-valine introduce rigidity.
2. Secondary Structure Formation
- α-Helices: Favor smaller side chains like alanine.
- β-Sheets: Can accommodate valine but struggle with bulky α-methyl groups.
- Loops & Turns: Prefer glycine or proline for flexibility.
Conclusion
In the Ramachandran map, α-methyl L-valine has the least allowed region due to high steric hindrance. This makes it less common in α-helices and β-sheets, impacting protein folding and structure. Understanding these restrictions is crucial in molecular biology and protein engineering.
36 Comments
Suman bhakar
March 27, 2025✅👍
Priyam choudhary
April 24, 2025✅
Khushi Singh
September 27, 2025Alpha methyl and L valine has least allowed region on plot
Neha Yadav
September 25, 2025In the Ramachandran map, alpha -methyl, L-valine has the least allowed region due to the presence of bulky R – gp which increases the steric hindrance
Aakansha sharma Sharma
September 25, 2025In the Ramachandran map, alpha -methyl, L-valine has the least allowed region due to the presence of bulky R – gp which increases the steric hindrance
Soniya Shekhawat
September 25, 2025the Ramachandran plot , α-methyl L-valine has the least allowed region due to high steric hindrance.
Kavita Choudhary
September 26, 2025In Ramachandran map alpha methyl and L valin has least allowed resion due to high stearic hindrance becuz bulky group is increse the stearic hindrance
Kirti Agarwal
September 26, 2025Alpha methyl L valine
Santosh Saini
September 26, 2025In the Ramachandran plot alpha methyl L- valine has the least allowed region due to high steric hindrance
Neelam Sharma
September 26, 2025In the Ramachandran map, α-methyl L-valine has the least allowed region due to high steric hindranc R grp bhot bda h
Dharmpal Swami
September 26, 2025Alpha methyl L valine has the least allowed region due to high steric hindrance
Mohd juber Ali
September 26, 2025Valine (form beta) and methyl has bulky R group on c alpha so R group value is more so phi and sai value less allowed reagion is least bcz stearic hindrance is increse
sakshi vijay
September 26, 2025due to presence of bulky R group that cause steric hinderance
alpha methyl ,L-valine has least allowed region ,means restricted value of phi and psi
Minal Sethi
September 26, 2025α-methyl L-valine has the least allowed region due to high steric hindrance.
Devika
September 26, 2025Alpha methyl l-valine has least allowed region bcz of its bulky methyl group
Kajal
September 26, 2025Alpha methyl L-valine have least allowed region due to bulky R group
Muskan Yadav
September 26, 2025In the Ramachandran map, α-methyl L-valine has the least allowed region due to high steric hindrance. This makes it less common in α-helices and β-sheets, impacting protein folding and structure.
Pallavi Ghangas
September 26, 2025alpha methyl valine
Priya khandal
September 26, 2025Alpha methyl valine has the least region because high static indence
HIMANI FAUJDAR
September 27, 2025Ans In Ramachandran Plot, α-methyl L-valine has least allowed region due to its bulky R gp ,show high steric hindrance makes it Least tolerated in α-helices and β-sheets.
Bhawna Choudhary
September 27, 2025α-methyl L-valine has the least allowed region due to high steric hindrance because of large bulky group
Manisha choudhary
September 28, 2025Alpha methyl L valine has bulky R group ,least allowed region due to steric hindrance
Arushi Saini
September 28, 2025In the Ramachandran map, alpha -methyl, L-valine has the least allowed region due to the presence of bulky R – gp which increases the steric hindrance
Mansukh Kapoor
September 28, 2025The correct answer is option 4th
Alpha-Methyl L-Valine group have the least allowed region on the ramachandra plot because they have the bulky group which least the steric hindrance
Sakshi Kanwar
September 28, 2025Additional methyl group on valine causes more steric hindernace …….values got more restricted to alpha methyl L valine
roopal sharma
September 28, 2025methyl group on valine causes more steric hinderance and restricted to alpha methyl L valine
Avni
September 28, 2025α-methyl L-valine has the least allowed region due to high steric hindrance
Anurag Giri
September 28, 2025Alpha-Methyl L-Valine has a bulky alpha-methyl CH3 group attached to the alpha carbon
Aafreen Khan
September 28, 2025Alpha-methyl , L-valine has the least allowed region due to high steric hindrance and bulky R group
Khushi Mehra
September 28, 2025Alpha- methyl L-Valine have least allowed region on Ramachandran plot because due to CH3 group , it has restricted phi and psi angle values.
Neeraj Sharma
September 28, 2025Least area will covered by alpha mehtly l valine on ramachandra plot as there is more hindrance for changing the angles because of bulky group
Heena Mahlawat
September 28, 2025Alpha-methyl L-valine least allowed due to its ch3 group i.e bulky
Divya rani
September 29, 2025Alpha methyl L valine is a bulky amino acid which create steric hindrance because of alpha methyl Group on alpha carbon.
Priyanshi sharma
September 29, 2025Correct answer is option 4
Priyanshi Sharma
September 29, 2025Alpha methyl L valine
Pooja
October 5, 2025Option 4 is correct
α-Methyl L-Valine due to Bulky α-methyl group increases steric hindrance