The amino acid sequence of hemoglobin I from Parasponia andersonii, a nonleguminous plant

Abstract

The complete ammo acid sequence of the hemoglobm I from nitrogen-fixing root nodules of the nonlegummous plant, Paraspomu andersonu, has been determined This dimeric protein consists of two ldentlcal polypepttde chains of 155 ammo acids and shows extensive sequence homology with other hemoglobms Homology between the hemoglobm I of P andersomz and the leghemoglobms of lupm and soybean nodules IS 41 and 39%, respectively The predicted secondary structure of P andersonu hemoglobm I has a high content of a-hehx, except for the E-helix, srmrlar hehces were predicted as those m the leghemoglobms The close homology of the sequences provides evidence that this nonlegummous hemoglobm shares the same genetic orlgm as the legume and animal hemoglobms HemoglobmNonlegummous plant Paraspoma andersonuAmmo acrd sequence Sequence homolog> PredIcted secondary structure Genetrc orrgm

cDNA and protein sequence of a major pea seed albumin (PA 2 : Mr?26 000)

“…PA2a and PA2b were cleaved with cyanogen bromide (CNBr) (12) and the resulting fragments were fractionated by reversed-phase HPLC on a Waters /zBondapak C18 column using an acetonitrile gradient. The isolated CNBr peptides were digested with trypsin (Worthington), chymotrypsin (Worthington) or Staphylococcus aureus V8 protease (Pierce) and the resultant peptides isolated by reversed-phase HPLC as described by Kortt et al (17). All peptides were sequenced manually by a modified Edman procedure (21) using 50o7o pyridine as the coupling buffer and extracting with nheptane-ethyl acetate (2 : 1, v/v) instead of benzene.…”

Amino acid sequences of hemoglobins I and II from root nodules of the non‐leguminous Parasponia rigida‐rhizobium symbiosis, and a correction of the sequence of hemoglobin I from Parasponia andersonii

“…A chymotryptic peptide with a blocked N terminus and composition of Asp, Ser(3), Glu, Val, Lys, Phe was also isolated. The sequence of the blocked tryptic peptide T1, can be deduced from its composition and the sequence of S. aureus protease peptide S1 [8], as S-S-S-E-V-N-K, consistent with the sequence of the N-terminal tryptic peptide in the DNAderived sequence. These results confirm that the N terminus of hemoglobin I contains the additional four residues observed in the DNA sequence and that the N-terminal serine is 10 20…”

“…A re-examination of the peptide data [8] revealed that Phe36 was missed in the original sequence because of the single-residue overlap provided by the peptic peptide overlapping Phe35 of T4 and Leu37 of C6, which failed to account for the extra Phe in the sequence Phe35-Phe-Leu37. The valine at 73 was missed owing to an error in collating the original sequence data.…”

“…This premise was disproved by the isolation of hemoglobin from the Rhizobium-induced nodules of Parusponia [6] and the Frankia-induced nodules of Casuarina [7]. The amino acid sequences of Parasponia andersonii hemoglobin I [8] and Casuarina glauca hemoglobin [9], and the gene sequence of P. undersonii hemoglobin I [lo] show considerable homology with those of the legume hemoglobins, indicating a common ancestral origin. These studies have confirmed Davenport's earlier report [l 11 that hemoglobin is indeed widely distributed in plants.…”

“…While the root nodules of P. andersonii contain a single major hemoglobin component [6], later designated hemoglobin I [8], with only traces of a second component (hemoglobin II), the nodules of P. rigida contain two components with the ratio hemoglobin-I : hemoglobin-I1 of 3.5: 1. Southern blot analyses of P. andersonii genomic DNA indicate the presence of only one hemoglobin gene locus [lo].…”