Question: mutations' effect on secondary structure
3
gravatar for lait
3.6 years ago by
lait140
lait140 wrote:

What I used t know is that when mutation takes place in a protein sequence and some amino acids are substituted with other amino acids having different chemical properties, then this will certainly alter the secondary structure of the protein sequence.

Recently I saw a case were 4 amino acids in a protein sequence are substituted with amino acids having same chemical properties (for example, E substituted with D), and this did affect the secondary structure of the sequence (beta sheets start/end positions changed).

  1. What is the explanation for this ?
  2. would this affect the function of the protein sequence also ?
ADD COMMENTlink modified 2.8 years ago by apa@stowers450 • written 3.6 years ago by lait140

Is this really within Biostars remit? Not exactly a bioinfx query

ADD REPLYlink written 2.8 years ago by Joe14k
0
gravatar for apa@stowers
2.8 years ago by
apa@stowers450
Kansas City
apa@stowers450 wrote:

This kind of sounds like an exam question, but, it is 9 months old...

Just about anything can impact the protein function, in theory. Depending on the situation, you can even get a disease phenotype from an L->I mutation, one of the most innocuous and common substitutions. Without knowing your exact case, it's hard to say why.

The basic chemical properties like polarity, pH, aromaticity aren't everything -- you also have pKas and isoelectric points, steric effects, helical propensities, cation affinities, types of bonds the side chain can engage in, etc, etc. Different amino acids are different!

One structural context may be very lax with amino acid properties (free loop), while others are very fine-tuned (inter-subunit bridge). You just don't know until you know (read: have the crystal structure).

Also, you can impact function without affecting secondary or tertiary structure. A mutation can affect the ability to interact with other proteins, receive PTMs, bind ligands, etc.

ADD COMMENTlink modified 2.8 years ago • written 2.8 years ago by apa@stowers450
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