1FNG

HISTOCOMPATIBILITY ANTIGEN

Entity

Entity ID	Chain ID	Description	Type	Chain length	Formula weight	Number of molecules	DB Name (Accession)	Biological source	Descriptive keywords
1	A, C	PROTEIN (MHC CLASS II I-EK, ALPHA CHAIN)	polymer	192	22361.1	2	UniProt (P04224) Pfam (PF00993) Pfam (PF07654) In PDB	Mus musculus (house mouse)
2	B, D	PROTEIN (MHC CLASS II I-EK, BETA CHAIN)	polymer	224	25376.3	2	UniProt (P02089) GenBank (AAA39594) Pfam (PF00969) Pfam (PF07654) UniProt (by SIFTS) (Q31163) In PDB	Mus musculus (house mouse)
3	A, B, C, D	2-acetamido-2-deoxy-beta-D-glucopyranose	non-polymer		221.2	6	Chemie (NAG)
4		water	water		18.0	507	Chemie (HOH)

Sequence modifications

B, D: 5 - 9 (UniProt: P02089)
B, D: 4 - 198 (GenBank: AAA39594)

Contents of the asymmetric unit

Polymers	Number of chains	4
	Total formula weight	95474.7
Non-Polymers*	Number of molecules	6
	Total formula weight	1327.2
All*	Total formula weight	96801.9

*Water molecules are not included.