Structure and sequence of the multihaem cytochrome c3

Area of Science:

• Biochemistry
• Structural Biology
• Microbiology

Background:

• Cytochrome c3 is a key electron carrier in sulfate-reducing bacteria.
• Understanding its structure is crucial for elucidating electron transfer mechanisms.

Purpose of the Study:

• To determine the high-resolution molecular structure of cytochrome c3 from Desulfovibrio desulfuricans.
• To characterize the arrangement and accessibility of its heme groups.

Main Methods:

• X-ray crystallography at 2.5 A resolution.
• Amino acid sequence determination and alignment.

Main Results:

• The molecular structure was solved, revealing a single polypeptide chain.
• A compact core of four non-parallel hemes with significant solvent exposure was identified.
• The determined structure is consistent with other cytochrome c3 sequences.

Conclusions:

• The solved structure provides detailed insights into cytochrome c3's architecture.
• The heme exposure suggests a role in facilitating electron transfer.
• This structure is representative of the broader cytochrome c3 family.