SIS (Sugar ISomerase) domains are found in many phosphosugar isomerases and phosphosugar binding proteins. SIS domains are also found in proteins that regulate the expression of genes involved in synthesis of phosphosugars. Presumably the SIS domain ...
SIS (Sugar ISomerase) domains are found in many phosphosugar isomerases and phosphosugar binding proteins. SIS domains are also found in proteins that regulate the expression of genes involved in synthesis of phosphosugars. Presumably the SIS domains bind to the end-product of the pathway.
3-hexulose-6-phosphate (PHI) catalyses the isomerisation between 3-hexulose 6-phosphate and fructose 6-phosphate. PHI is part of the ribulose monophosphate (RuMP) pathway, which in one direction removes the toxic metabolite formaldehyde by assimilation into fructose-6-phosphate [PMID:10648518]. In the other direction, in species lacking a complete pentose phosphate pathway, the RuMP pathway yields ribulose-5-phosphate, necessary for nucleotide biosynthesis, at the cost of also yielding formaldehyde. These latter species tend usually have a formaldehyde-activating enzyme to attach formaldehyde to the C1 carrier tetrahydromethanopterin.
Defined by 7 residues: ARG:A-58 [auth A-57]HIS:A-61 [auth A-60]ASP:A-161 [auth A-160]ARG:B_2-47 [auth B_2-46]SER:B_2-89 [auth B_2-88]SER:B_2-150 [auth B_2-149]GLU:B_2-153 [auth B_2-152]