1 L K C N K L V P L F Y K T C P A G K N L C Y K M F M V A T P

31 K V P V K R G C I D V C P K S S L L V K Y V C C N T D R C N

(1) Is this a new toxin? Please help him to identify this toxin.

(2) Can you find proteins that share sequence homology with

this toxin? Show them in multiple alignment form.

(3) Please predict its secondary structure.

(4) Please show its charge distribution.

Ans:

(1)ID : 2CRS

Header : CARDIOTOXIN

Compound : Cardiotoxin iii (NMR, 13 structures)

Source : Taiwan cobra (naja naja atra) venom

(3)Secondary structure:

Garnier plot of Cardiotoxin iii (NMR, 13 structures)

60 aa; DCH = 0, DCS = 0

. 10 . 20 . 30 . 40 . 50 . 60

LKCNKLVPLFYKTCPAGKNLCYKMFMVATPKVPVKRGCIDVCPKSSLLVKYVCCNTDRCN

helix H HHH HHHH

sheet EEEEEEEEE EEEEE E E EEEEE EEEEEEEE

turns TTT TTTT T T TT TTTT TTTTTT

coil C C

Residue totals: H: 8 E: 29 T: 21 C: 2

percent: H: 18.2 E: 65.9 T: 47.7 C: 4.5

(4)Charge distribution:

1 0+00+00000 0+00000+00 00+0000000 +000++000- 000+00000+ 000000-+00

CHARGE CLUSTERS.

Positive charge clusters (cmin = 13/30 or 18/45 or 22/60): none

Negative charge clusters: not evaluated (frequency of - < 5%, too low)

Mixed charge clusters (cmin = 15/30 or 20/45 or 25/60): none

(2)