Structure And Function Of AtNRAMP3 Transporter In Arabidopsis Thaliana

Metal ions are essential for the normal development of plants,but overdose will cause plant poisoning to affect their growth.The organism maintains the mechanism of automatic regulation and balance,which regulates the absorption and transportation of metal ions to control the content of metal ions in the plant.This mechanism is mainly composed of plant metal ion transport proteins.The family of NRAMP(Nature Resistance Associated Macrophage protein)is one of the important members transporters and is defined as a new family of transgenic divalent metal ion-related proteins,which is highly conserved in evolution and homology.The gene has been identified in a variety of organisms,widely found in prokaryotes and eukaryotes.In this study,the sequence of its target gene AtNRAMP3,Which was obtained by searching the gene,primer design and experimental operation.The gene size was 1530bp,and the localization of AtNRAMP3 on the vacuolar membrane was confirmed by subcellular localization.It has been reported that AtNRAMP3 mainly regulates the transport of Fe,Mn and Cd.We obtained yeast wild-type WT and its mutant ?Ccc1,?Smf1 and AYcfl.The main amino acid of this transgenic protein NRAMP3 was used to study its molecular structure and function.We found some highly conserved amino acid sites by comparing the NRAMP transporter family gene sequence.The amino acid sites were mutated to alanine,and the expression vector was transformed with PFL61 vector to transform the yeast mutant.The growth of yeast spots,presumably the amino acids that affect their function,and the structural properties of AtNRAMP3.The main results are as follows:In order to explore the effect of key amino acid mutations on the structure and function of AtNRAMP3,we differentiated the expression vector into different yeast mutants.We studied the growth of yeast mutant.We speculated that D72,N75,C245 and M248 were composed of metal ions The amino acid of the site has an important effect on the transport of Fe at AtNRAMP3.The mutations of these four amino acids change the selectivity of the metal ions so that AtNRAMP3 can not transfer iron ions,and the mutations of D72,N75 and M248 also render AtNRAMP3 losing the function of Mn,Suggesting that these three points for the transfer of Fe and transfer Mn has an important role,so that the transporter lost ion selectivity,M248 mutations in methionine at this site make AtNRAMP3 lose the function of Fe?Mn and Cd at the same time,Suggesting that this amino acid site is critical to the selectivity of metal ions.Some of the amino acids on the transmembrane spikes TM1 and TM6 can not bind to metal ions by changing the conformation of AtNRAMP3 in an inward or outward locked state,where mutations of a key amino acid P249 on transmembrane spiral TM6 cause AtNRAMP3 to lose the function of Cd,but also retained the Fe and Mn transport function,the amino acid sites for our study of improved plant heavy metal poisoning is very important.Some of the highly conserved amino acid mutations also deprive AtNRAMP3 of the ability to transport Fe or Mn ions,and how these highly conserved amino acids affect the AtNRAMP3 structure and how it affects its function requires further investigation.