HeliQuest α-helix
Search of putative helices with defined parameters in protein database


Results by Email ?

yes
Email:
Enter your Email address to receive your results

no
The results of your query will be available by a html file

Compute parameters of a known sequence: here. Use our web server to compute sequence parameters


Physico-chemical parameters

Reference value

Hydrophobicity <H>

0.45
Minimal <H>
Maximal <H>
Enter the minimal and maximal <H> values

Hydrophobic moment <µH>

0.7
Minimal <µH>
Maximal <µH>
Enter the minimal and maximal <µH> values

Net charge z

0
Minimal z
Maximal z
Enter the minimal and maximal z values

Sequence statistics

Polar amino-acid composition

Reference value

Minimal number of polar residues + glycine

8
Enter the minimal number of polar residue (EDKRSTNQH)+G

Minimal number of uncharged residue

6
SER
THR
ASN
GLN
HIS
Enter the minimal number of selected residue

Minimal number of glycine

1
Enter the minimal number of glycine

Maximal number of charged residue

3
Enter the maximal number of charged residue

Special residue

Is proline accepted ? (at i, i+3 / n-3, n)

yes
no

Is cysteine accepted ?

yes
no

Use geometric rules

yes
no
A specific algorithm refines the identification of well-defined amphipathic helices

DataBase

SwissProt Database

Human
Rat
Mouse
Yeast
Personnal DataBase

The personal database must be in a FASTA format

BlackList (Hypothetical, Putative, Probable)

yes
no
Elimination of protein whose designation contains one of the terms of the blacklist

Helical wheel representation

One-letter code size proportional to amino acid volume

yes
no

Rotation of the helix to align vertically the <µH> vector

yes
no