Structural Deterioration in Produce: Phospholipase D, Membrane Deterioration, and Senescence - Postharvest Biology and Technology of Fruits, Vegetables, and Flowers - page 217

1 2 3

β -1 β -2 β -3 β -4

LePLD α 16 LH GTLHVTIFEV DNLQ G EEE GGHFFSKI KQHF E ETVGIGKGTP K LYATIDLE KARV GRTRIIE N E 70
FaPLD α 19 LH GTLHATIYEV DKLH G S--SG NFLRKI TGKL E ETVGLGKGVS K LYATVDLE RARV GRTRVIE K E 71
CmPLD α 16 LH GTLHATIYEI DRLH T GG-S SNVFSML RQNF E EAVGIGKGQT K LYATIDLE KARV GRTRILE S E 69
CsPLD α 16 LH GTLHATIYEI DRLH T GG-S SNVFSML RQNF E EAVGIGKGQT K LYATIDLE KARV GRTRILE S D 69
CmPLD α 26 LH GTLHVTIYEV DKLH S GG--R NFLKQL VENV E EAVGFGRGIT R LYATIDLE KARV GRTRRLE R E 68
LePLD α 26 LH GTLHVTIFEV DKLR T NF-G REIFNKV VQGI E GAIGFNKTAS T LYATIDLG KARV GRTRLLD - E 68
LePLD α 3

6 LH GTLHVTIFEV DRLH T NF-G RDFFNKV VQGI E GAIGFNKAAS R LYATIDLG KARV GRTRLLD - D 68

4 5

β -1 β -6 β -7 β -8

LePLD α 1
FaPLD α 1
CmPLD α 1
CsPLD α 1
CmPLD α 2
LePLD α 2
LePLD α 3

71 P KNPRWYESFH IYCAHMA SNVIFTIK D D N PFGA SLIGRAYVPV EELLEGE EIDKWVEI MDKEMNP 135
72 P SNPNWSESFH IYCAHVA ANVIFTVK E S N PIGA SLIGRAYVPV EQLIEGE EVDTWAKI LDDKKNP 136
70 P SNPRWYESFH IYCAHKA SNVIFTVK D D N PIGA TLIGHAYVPV EDIVDGE EVDRWVPI LDENQNP 134
70 P SNPKWNESFH IYCAHKA SNVIFTVK D D N PIGA TLIGRAYVPV EDIVDGE EVDKWVPI LDENQNP 134
69 H SNPKWYETFH IYCAHMA SNIIFTVK D D N PIGA TLIGRAYLPV REIIRGD EVDKWVPI LDEQKKP 133
69 H KNPRWYESFH IYCAHMA SDVVFTVK A D N PIGA ELIGRAYLPV EQLIVGE VVDEWLEI LDTERKP 133
69 H KNPRWYESFH IYCAHMA ANVIITVK F D N PIGA EVIGRAYFPV QQLLDGE EVDEWLEI LNTERKP 133

(a)

AS-1
300 QGTDVNCVLCPRNPDNGGSFVQDIQISTMFTH H Q K IIVV D SALPSGESEKRRILSFVGGID 360
301 QNTDVNCVLCPRNPDGGGSIVQGAQISTMFTH H Q K IVVV D SEMPNGGSQSRRIVSFVGGLD 361
299 QDTDVHCVLCPRNPDDGGSIVQDLQISTMFTH H Q K IVVV D SPMPNGDSDRRRIVSFVGGID 359
299 QDTDVHCVLCPRNPDDGGSIVQDLQISTMFTH H Q K IVVV D SPMPNGDSDKRRIVSFVGGID 359
298 ANTDVHCVLCPRNPDDGANVIQDIAVGTMFTH H Q K IVVV D SALPNGDPSKRRIVSFVGGLD 358
298 ENSEVHCVLCPRNPDDGRSIIQNIEIGTMFTH H Q K IVVV D GELPNGDTERRRIVSYIGGID 358
298 RGTQVSCVLCPRNPDDGRSIIQNIEIGTMFTH H Q K IVIV D GEMPNGDRERRRIVSYIGGLD 358

LePLD α 1
FaPLD α 1
CmPLD α 1
CsPLD α 1
CmPLD α 2
LePLD α 2
LePLD α 3

(b)

PEST-rich sequence AS-2
629 KK SGEYEPSESPEPDS NYMRAQEARR FMIYV H S K MMIV D DEYIIV GS A N INQRSMDGARD 688
630 KK DGEYEPSEAPEADSD YIRAQEARR FMIYV H T K MMIV D DEYIII GS A N INQRSMDGARD 689
628 KR SGEYEPSEAPEEDSD YLRAQQARR FMIYV H T K MMIV D DEYIIV GS A N INQRSMDGARD 687
628 KR SGEYEPSEAPEEDSD YLRAQQARR FMIYV H T K MMIV D DEYIIV GS A N INQRSMDGARD 687
627 KK PGEYEPSESPDENSD YLRAQQSRR FMIYV H S K MMIV D DEYIIV GS A N INQRSMDGARD 686
627 KK TGEYEPSESPEPDSD YQKAQEARR FMIYV H A K MMIV D DEYIII GS A N INQRSMDGARD 686
627 KKRG EYEPCEPPEPNS GYHKAQEARR FMIYV H S K MMIV D DEYIII GS A N INQRSMDGARD 686

LePLD α 1
FaPLD α 1
CmPLD α 1
CsPLD α 1
CmPLD α 2
LePLD α 2
LePLD α 3

(c)

Alignment of the encoded amino acid sequences of PLD alphas from tomato (LePLD α 1, LePLD α 2,

Fig. 9.12

and LePLD 1)

comparing (a) the C2 Ca 2 + /phospholipid-binding domain, (b) the first HKD active site motif (AS-1), and
(c) a PEST-rich proteolysis-targeting sequence plus the second HKD-GSN active site motif (AS-2).

α 3), strawberry (FaPLD α 1), honeydew melon (CmPLD α 1 and CmPLD α 2), and cucumber (CsPLD α

website showed the presence of a C2 Ca 2 + /phospholipids-binding domain and two PLD
active site motifs, HxKxxxxD and HxKxxxxDxxxxxxGSxN (Pappan et al., 1997; Stuckey
and Dixon, 1999; Wang, 2000), in each of the seven PLD alphas from tomato, strawberry,
melon, and cucumber (Fig. 9.12). Despite the relatively poor conservation between PLD
alphas and other plant PLDs (about 40-44% identity with PLDs beta, gamma, and delta),
these features are present in all types of plant PLDs except PLD zeta, which includes plextrin
and phox homology domains and lacks the C2 domain (Wang et al., 2006).
C2 domains occur in a variety of proteins that in one way or another interact with mem-
branes. Calcium binding to specific sites in the C2 domain confers a charge to the protein,
facilitating electrostatic association with anionic sites on a membrane (Ponting and Kerr,
1996; Nalefski et al., 1997). Thus, in plant PLDs including a C2 domain, calcium-activated
membrane association of an otherwise soluble, cytosolic enzyme appears to involve an