Amino Acid Sequence of a Ferredoxin from Thermoacidophilic Archaebacterium, Sulfolobus acidocaldarius. Presence of an N6-Monomethyllysine and Phyletic Consideration of Archaebacteria1

Abstract

The amino acid sequence of a ferredoxin from a thermoacidophilic archaebacterium, Sulfolobus acidocaldarius, was determined by a combination of various conventional methods to be as follows: Gly-Ile-Asp-Pro-Tyr-Arg-Thr-His-Lys-Pro-Val-Val-Gly-Asp-Ser-Ser-Gly-His- Lys-Ile -Tyr-Gly-Pro-Val-Glu-Ser-Pro-Lys(Me)-Val-Leu-Gly-Val-His-Gly-Thr-Ile-Val -Gly-Va l-Asp-Phe-Asp-Leu-Cys-Ile-Ala-Asp-Gly-Ser-Cys-Ile-Thr-Ala-Cys-Pro-Val-As n-Val-P he-Gln-Trp-Tyr-Glu-Thr-Pro-Gly-His-Pro-Ala-Ser-Glu-Lys-Lys-Ala-Asp-Pro-V al-Asn- Glu-Gln-Ala-Cys-Ile-Phe-Cys-Met-Ala-Cys-Val-Asn-Val-Cys-Pro-Val-Ala-Ala- Ile-Asp -Val-Lys-Pro-Pro. It was composed of 103 amino acid residues giving a molecular weight of 10,908 excluding Fe and S atoms. This ferredoxin contained an N6-monomethyllysine residue at position 29 which was determined by a comparison of the elution profile of the acid hydrolysates of the protein and peptides on an amino acid analyzer with three methyl derivatives of lysine and also by field desorption mass spectrometry of a purified peptide. The ferredoxin has only 7 cysteine residues, which probably participate in constructing the Fe-S clusters of this ferredoxin, indicating the presence of a unique chelate structure. Comparison of this ferredoxin with other archaebacterial ferredoxins indicated that the archaebacteria might have multiple origins in an evolutionary tree.

Structural Conservation of the Isolated Zinc Site in Archaeal Zinc-containing Ferredoxins as Revealed by X-ray Absorption Spectroscopic Analysis and Its Evolutionary Implications

“…1). The same spacing of consensus cysteine residues was found in other zinc-containing ferredoxin sequences (6,10,11,13,53), and was proposed to be attributed to the similarity of the pattern of hyperfine-shifted resonances of 1 H-NMR spectra of the 7Fe form of zinc-containing ferredoxins 5 to those of the 3Fe-, 4Fe-, and 8Fe-containing ferredoxins (53,54). In the Azotobactertype 7Fe-containing ferredoxins with a long C-terminal region, the cysteine ligand residues are arranged more asymmetrically due to the insertion of a short amino acid sequence stretch at the cluster binding motif (54 -58).…”

The protein sequence of glutamate dehydrogenase from Sulfolobus solfataricus, a thermoacidophilic archaebacterium

“…Only in the ferredoxin from S. acidocaldarius was the presence of a N-t:-methyllysine detected [23]. It should be pointed out that most of the recently reported sequences of thermostable enzymes are deduced from DNA, thus post-translational modifications could not be evidenced.…”

Ferredoxin III of Desulfovibrio africanus: sequencing of the native gene and characterization of a histidine-tagged form

“…This latter feature has only been observed in one other case, the closely related FdI from D. ulgaris (Miyazaki) [5]. The Cys"% Asp variation occurs somewhat more frequently, for example, in [3Fe-4S]-cluster-containing Fds from Pyrococcus furiosus, Bacillus schlegelii, Sulfolobus acidocaldarius, Thermoplasma acidophilum and Desulfurolobus ambi alens [6][7][8][9][10]. [3Fe-4S] clusters can react with metal ions (M)s to produce heterometal cubane clusters [M : 3Fe-4S]# +/"+ , but the ease and readiness with which this occurs varies widely between proteins.…”