摘要：AbstractHMA (heavy metal associated) is a member of the ATPases protein family involved in metal transport in plants. This study characterizes several HMA3 homologs and infers their molecular functions in different plant species. ArabidopsisAtHMA3(AT4G30120) was used as a reference to retrieve 11 HMA3 homologs having 97–100% query cover, 535–542 residues, 56,983 to 58,642 (Da) molecular weight, and 5.74 to 8.16 pI value, 29.10 to 33.89 instability index, and 0.222 to 0.380 grand average of hydropathicity. Topological analyses showed 4 transmembrane domains in these HMA3 homologs positioned similarly in terms of cytoplasmic and non-cytoplasmic regions along with ∼22–28% α-helices, ∼22–28% extended strands, and ∼50% random coils. HMA3 protein ofArabidopsis lyratasubsp. lyrata andEutrema salsugineumare located at chromosome 2, while others are positioned at chromosome 4. All these HMA3 homologs are localized in the plasma membrane sharing a few common biological and molecular functions. Besides, theseHMA3genes contain 8–9 exons in which promoter positions are varied among the homologs. Thecis-acting elements ofHMA3genes were projected to be involved with stress response, anaerobic induction, and light-responsive regulation in plants. Three out of five motifs encode E1-E2_ATPase involved in proton-pumping in the plasma membrane. TheArabidopsis thalianaHMA3 protein clustered withCamelina sativaandCapsella rubellashow a close phylogenetic relationship. Also,AtHMA3exhibits a close association withAtHMA3withMTPA2,ZAT,NRAMP3,IRT2,andNRAMP2under the local network of AtHMA3 linked to metal transport. Further,AtHMA3is most potentially expressed during senescence, germinating seed, seedlings, young rosette, bolting, and young flower. In addition,AtHMA3showed a significant upregulation (>6.0 fold) under Fe-deficiency. These findings may provide essential background to perform wet-lab experiments to understand the role ofHMA3in metal homeostasis.
