Table 4.
Amino acid alignment of three D. pulex metallothionein genes against those from other crustaceans (decapods) and from selected insectsa.
| Protein domains | |-------------- Beta --------------| |------------------- Alpha --------------------| |
| Mtn1 Anopheles gambiae | MPCKCCGN-DCKCTSG---CGSGQPCAT---DCKCACASGGCKEKS------------------------------GGCCGK-- |
| Mtn2 Anopheles gambiae | MPCKTCVA-DCKCTSP--NCGAGCGCES---RCTCPCKDGAK----------------------------------EGCCK--- |
| MtnA Drosophila melanogaster | MPCP-CGS-GCKCASQ--ATKGSCNCGS---DCKCG---------------------------------GDKKSA-CGCSE--- |
| MtnB Drosophila melanogaster | MVCKGCGT-NCQCSAQ--KCGDNCACNK---DCQCVCKNGPK----------------------------------DQCCSNK- |
| MtnC Drosophila melanogaster | MVCKGCGT-NCKCQDT--KCGDNCACNQ---DCKCVCKNGPK----------------------------------DQCCKSK- |
| MtnD Drosophila melanogaster | MGCKACGT-NCQCSAT--KCGDNCACSQ---QCQCSCKNGPK----------------------------------DKCCSTKN |
| CuMtn2 Callinectes sapidus CRAB | MPCG-CGT-SCKCGSGKCCCGSTCNCTTCPSKQSCSCNDGACGSAC--------------QCKTSCCCGADCK---CSPCPMK- |
| Mtn1 Callinectes sapidus CRAB | MPGPCCND-KCVCQEG--GCKAGCQCTS----CRCS-PCQKCTSGC--------------KCATKEECSKTCTKP-CSCCPK-- |
| Mtn2 Callinectes sapidus CRAB | MPDPCCND-KCECKEG--ECKTGCKCKS----CRCP-PCDKCSSEC--------------KCTSKEECSKTCSKP-CSCCP--- |
| Mtn1 Scylla serrata CRAB | -PGPCCND-KCVCKEG--GCKEGCQCTS----CRCS-PCEKCSSGC--------------KCANKEECSKTCSKA-CSCCPT-- |
| Mtn2 Scylla serrata CRAB | MPDPCCID-KCDCKEG--ECKTGCKCTS----CRCP-PCEQCSSGC--------------KCANKEDCRKTCSKP-CSCCP--- |
| Mtn1 Potamon potamios CRAB | -PDPCCAEGTCECEEG--KCKAGCKCTS----CRCS-PCEKCTSEC--------------ECKSKEECAKNCTKP-CSCCP--- |
| Mtn Carcinus maenas CRAB | MPDPCCID-KCECKEG--GCKAGCKCTS----CRCT-PCEKCSSGC--------------KCTTKEDCCKTCTKP-CSCCP--- |
| Mtn Eriocheir sinensis CRAB | MPDPCCND-KCECKEG--KCEAGCKCTS----CRCP-PCEKCSSGC--------------KCGSKEDCCKTCSKP-CSCCP--- |
| Mtn Portunus pelagicus CRAB | MPDPCCID-KCECKEG--KCEAGCKCTS----CRCP-PCEKCSSGC--------------KCGSKEDCCKTCSKP-CSCCP--- |
| Mtn Panulirus argus LOBSTER | MPGPCCID-KCECAEG--KCKSGCQCKS----CTCSTPCDKCTTAC--------------CCSTKEECASKCTKP-CKCCP--- |
| Mtn Homarus americanus LOBSTER | MPGPCCKD-KCECAEG--GCKTGCKCTS----CRCA-PCEKCTSGC--------------KCPSKDECAKTCSKP-CKCCP--- |
| Mtn Astacus astacus CRAYFISH | MPGPCCND-VCECAAG--GCKTGCVCTS----CRCS-PCDKCTSGC--------------KCPSKEECAKTCSKP-CECCP--- |
| Mtn1 Daphnia pulex cDNA | MTKD--------------CCQGKCSCGD---NCKCGPNCAQCPAAA----TCACATGGECKCSGNCQCSTSCPCK-SACCK--- |
| Mtn2 Daphnia pulex cDNA | MPKECV------------RCQNGCTCGD---DCKCAANCIKCPTASSQGETCKCSTPGGCTCGTNCQCGASCVCKASSCCK--- |
| Mtn3 Daphnia pulex cDNA | MPNACCQN-KCSCGSGCNCCQSKCTCGS---GCKCGPNGAPCQNSA-----CICATGGG-GCGSDCRCPTSCGCK-TSCCK--- |
| Mtn3 Daphnia magna cDNA¥ | MPNVCCQN-NCSCGNGCTCCQSKCTCGS---GCKCGPNGAPCQNSA-----CICATGGG-GCGSDCRCPVSCGCK-TSCCK--- |
| Cysteine residues | 0 00 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 2 2 2 22 |
| 1 23 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 34 | |
| Metal binding | ** * * * * * * * * * * * * * * ** |
aCysteine residues are bold for sites that are conserved in crustacean and insect genes (residues 3–10, 23, 24) and underlined when residues are clade-specific. Assuming a correct alignment, residues 2, 12, 13, 17, 19 and 20 are conserved in all (or most) of the crustacean genes, whereas residues 14 and 22 are conserved in the decapod genes. The residues 15, 16, 18 and 21 are exclusively found in the Daphnia genes (representing branchiopods) and based on the limited sampling of insect genes (from two dipterans), residues 1 and 11 are excluded in the crustacean genes. Domain partitions and metal bind residues (*) are based on experimental evidence from decapod proteins (Valls et al. [41]). ¥ Poynton et al. [19] provides full translation.