24117
Four highly conserved cysteine residues were shown to be required for coordinating the iron - sulfur cluster , and substitution of any of these Cys residues with Ser or Ala within the context of lambda gpL abolished biological activity .
 Chemical: cysteine; Chemical: iron - sulfur; Chemical: Cys; Chemical: Ser; Chemical: Ala
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: cysteine; Chemical: iron - sulfur; Chemical: Cys; Chemical: Ser; Chemical: Ala