4P3E

Structure of the human SRP S domain

Entity

Entity ID	Chain ID	Description	Type	Chain length	Formula weight	Number of molecules	DB Name (Accession)	Biological source	Descriptive keywords
1	A	SRP RNA (124-mer)	polymer	125	40549.2	1	GenBank (177793)	Homo sapiens
2	B	Signal recognition particle 19 kDa protein	polymer	128	14791.1	1	UniProt (P09132) Pfam (PF01922) In PDB	Homo sapiens (Human)	SRP19
3	C	Signal recognition particle subunit SRP68	polymer	216	25604.2	1	UniProt (Q9UHB9) Pfam (PF16969) In PDB	Homo sapiens (Human)	SRP68, Signal recognition particle 68 kDa protein
4	A	MAGNESIUM ION	non-polymer		24.3	4	Chemie (MG)

Sequence modifications

A: 115 - 236 (GenBank: 177793)

PDB	External Database	Details
G 114	-	engineered mutation
U 237	-	engineered mutation
A 238	-	engineered mutation

B: 1 - 120 (UniProt: P09132)

PDB	External Database	Details
Leu 121	-	expression tag
Glu 122	-	expression tag
His 123	-	expression tag
His 124	-	expression tag
His 125	-	expression tag
His 126	-	expression tag
His 127	-	expression tag
His 128	-	expression tag

C: 39 - 246 (UniProt: Q9UHB9)

PDB	External Database	Details
Met 31	-	initiating methionine
Gly 32	-	expression tag
His 33	-	expression tag
His 34	-	expression tag
His 35	-	expression tag
His 36	-	expression tag
His 37	-	expression tag
His 38	-	expression tag
Asp 108	Glu 116	engineered mutation

Contents of the asymmetric unit

Polymers	Number of chains	3
	Total formula weight	80944.5
Non-Polymers*	Number of molecules	4
	Total formula weight	97.2
All*	Total formula weight	81041.7

*Water molecules are not included.