PDB file SEQRES have different data?

Question

In PDB file, SEQRES represent the aminoacids but some pdb file present the "GLC" and some other. for example

SEQRES   1 A   26  GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC          
SEQRES   2 A   26  GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC          
SEQRES   1 B   26  GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC          
SEQRES   2 B   26  GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC GLC       

In that PDB ID: 1C58
What are this and What are represent the SEQRES?

Answer 1

The pdb file that you mention is entitled:

V-Amylose at atomic resolution: X-ray structure of a cycloamylose with 26 glucose residues (cyclomaltohexaicosaose).

So, it isn't a protein at all, it is a circular oligosaccharide consisting of 26 glucose (GLC) residues. I imagine that the usual fields in the pdb file have been fudged to accommodate this.