1XXM

The modular architecture of protein-protein binding site

Entity

Entity ID	Chain ID	Description	Type	Chain length	Formula weight	Number of molecules	DB Name (Accession)	Biological source	Descriptive keywords
1	A, B	Beta-lactamase TEM	polymer	263	28805.9	2	UniProt (P62593) Pfam (PF00144) Pfam (PF13354) In PDB	Escherichia coli	TEM-1; TEM-2; TEM-3; TEM-4; TEM-5; TEM-6; TEM-8/CAZ-2; TEM-16/CAZ-7; TEM-24/CAZ-6; IRT-4; Penicillinase
2	C, D	Beta-lactamase inhibitory protein	polymer	165	17330.2	2	UniProt (P35804) Pfam (PF07467) In PDB	Streptomyces clavuligerus	BLIP
3	C, D	CALCIUM ION	non-polymer		40.1	2	Chemie (CA)
4		water	water		18.0	417	Chemie (HOH)

Sequence modifications

A, B: 26 - 288 (UniProt: P62593)

PDB	External Database	Details
Ile 84	Val 82	engineered mutation
Ala 104	Glu 102	engineered mutation
Ala 105	Tyr 103	engineered mutation

C, D: 1001 - 1165 (UniProt: P35804)

PDB	External Database	Details
Ala 1074	Lys 110	engineered mutation
Ala 1142	Phe 178	engineered mutation
Ala 1143	Tyr 179	engineered mutation

Contents of the asymmetric unit

Polymers	Number of chains	4
	Total formula weight	92272.2
Non-Polymers*	Number of molecules	2
	Total formula weight	80.2
All*	Total formula weight	92352.3

*Water molecules are not included.