Basic HTML Version
Triticeae Genomics and Genetics 2012, Vol.3, No.1, 1
-
8
http://tgg.sophiapublisher.com
4
1.3 Characteristics and secondary structures of
DHN6
Analyses of physical and chemical characteristics of
three types of rowed barley found that DHN6, a
stable and highly hydrophilic basic protein, was
composed of 18 amino acid residues, and enriched
Gly, but was absent of Trp and Cys (Table 2). The
results showed that the molecular weight of DHN6 in
BZ-12 was the largest, in despite of containing a Gly
peptide, but the Gly content and hydrophilic index is
not the highest, whereas, the hydropathicity parameter
in BZ-26 and BZ-16 was the highest, and BZ-26 was
the stablest. Therefore, hydropathicity index was not
related to instability index, molecular weight and
contents of Gly.
To predict the relationship between characteristic and
secondary structure, we analyzed the secondary
structure of DHN6 among two-, four-, and six-rowed
barley (Table 3). The results showed that the secondary
structure of DHN6 involving four basic structures
such as alpha helix, beta turn, extrended strand, and
random coil. We also knew that from table 3 the
percentage of extrended strand and random coil was
highest, reached up to 80%, they were the main
component of DHN6 secondary structure. Furthermore,
The highest ratio of alpha helix and random coil was
observed in two-rowed barley (BZ-26), was 7.41%
and 60.29%, respectively. Moreover, three alpha
helixes formed by K-sequence appeared in the
different rowed barley and hull-less barley (Figure 4).
1.4 Phylogenetic analysis of amino acid sequences
in DHN6
Based on the characteristic sequences and conserved
motifs of DHN6 in GenBank, we selected 21 species
to construct the phylogenetic tree and study the
relationships of phylogenetic and molecular evolutionary,
selecting the highest scores of
E
-values in the same
species. As shown in Figure 5, three scaffolds of those
species were consisted in the molecular evolutionary,
and the tested materials were attributed to the same
branch including GU216698 and hull-less barley
(AF043091). Notably, the separated genetic relationship
was detected in the woody plants such as
Prunus
persica
(CAC00637),
Pinus sylvestris
(CAD54622)
and
Picea abies
(ABU89751).
Table 2 Characteristics of DHN6 proteins in the samples and hull-less barley
Barley
Molecular weight
Isoelectric point
Contents of Gly, Cys and Trp
Instability
index
Hydropathicity
index
BZ-12
49.68
8.04
Gly(32.3)
Cys(0.2)
Trp(0)
-
6.84
-
0.748
BZ-16
47.58
8.09
Gly(32.5)
Cys(0)
Trp(0)
-
6.76
-
0.745
BZ-26
46.17
8.80
Gly(32.3)
Cys(0)
Trp(0)
-
6.89
-
0.726
AF043091
47.65
8.09
Gly(32.5)
Cys(0)
Trp(0)
-
6.56
-
0.749
Note: The same information as table 1
Table 3 Percentage of secondary structure of DHN6 proteins in the samples and hull-less barley
Barley
Number of helix
Alpha helix
Beta turn
Extrended strand
Random coil
BZ-12
3
6.88%
9.18%
27.53%
56.41%
BZ-16
3
7.17%
8.76%
24.10%
59.96%
BZ-26
3
7.41%
7.82%
24.49%
60.29%
AF043091
3
7.17%
8.76%
25.30%
58.76%
Note: The same information as table 1