A standard numbering scheme for thiamine diphosphate-dependent decarboxylases

Area of Science:

• Biochemistry
• Structural Biology
• Bioinformatics

Background:

• Standard numbering schemes are crucial for identifying functionally relevant residues in protein families.
• A numbering scheme for thiamine-diphosphate (ThDP)-dependent decarboxylases is currently missing, hindering sequence analysis.
• This protein family includes diverse enzymes like pyruvate decarboxylases and acetohydroxyacid synthases.

Purpose of the Study:

• To develop and validate a standard numbering scheme for the ThDP-dependent decarboxylase family.
• To facilitate unambiguous identification of functionally and structurally important amino acid positions.
• To enable systematic analysis of sequence-function relationships within this enzyme superfamily.

Main Methods:

• A profile hidden Markov model (HMM) was constructed using representative sequences.
• The pyruvate decarboxylase from S. cerevisiae (PDB: 2VK8) was selected as the reference structure.
• The numbering of the reference sequence was transferred to all family members and integrated into the TEED database.

Main Results:

• A validated standard numbering scheme for ThDP-dependent decarboxylases was successfully developed.
• The scheme allows for reliable sequence alignment and identification of corresponding positions.
• Functional and structural analyses of relevant positions in the superfamily are now feasible.

Conclusions:

• The developed numbering scheme is a valuable tool for ThDP-dependent decarboxylase research.
• It facilitates reliable communication of mutation data and analysis of sequence-encoded properties.
• The robust method can be adapted for other protein families.