Analysis of NMR data and global fold of the [Fe4–S4] ferredoxin I from Desulfovibrio desulfuricans norway

✍ Scribed by Evelyne Lebrun

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 269 KB
• Volume: 36
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199812)36:12<913::aid-omr389>3.0.co;2-2

✦ Synopsis

The oxidized form of the ferredoxin I from Desulfovibrio desulfuricans Norway (DdN Fd I) [Fe 4

ÈS 4 ] was investigated by 1H and 13C NMR spectroscopy. The sequence-speciÐc 1H assignments of 93% of the amino acid residues of the whole protein, a complete determination of its secondary structure and an identiÐcation of a disulÐde bridge are reported. The secondary structure of DdN Fd I was determined from both sequential and spatial NOEs. These NOEs reveal two anti-parallel b-sheets including Thr1ÈIle4 and Glu59ÈIle56, Val22ÈIle26 and Thr35ÈLys31, one helical segment (ranging from Ala41 to Asp49) and three tight turns. Three-dimensional features of DdN Fd I were evidenced from long-range NOE cross peaks between the secondary structural elements of the protein. Among them, a possible disulÐde bridge, located between the pair of cysteines which are not coordinated to the cluster, was indicated by a 13CÈ1H HSQC experiment at natural abundance. The comparison of secondary structural elements and tertiary contacts of DdN Fd I protein with those of ferredoxins from mesophilic bacteria Desulfovibrio gigas and Desulfovibrio africanus and that from the hyperthermostable archaeon T hermococcus litoralis conÐrms that DdN Fd I exhibits the same global protein folding topology as the others. The chemical shifts of DdN Fd I were compared with those of other monocluster-type ferredoxins. They show a peculiar conservation of the hydrophobic core of these ferredoxins.