1ICI: SIR2 homolog-NAD complex

Crystal structure of a SIR2 homolog-NAD complex. Determined by X-ray diffraction at 2.1 Å resolution. Released 2 May 2001.

Method: X-ray diffraction
Resolution: 2.1 Å
Organism: Archaeoglobus fulgidus
Chains: 2
Atoms: 4,249
Mol. weight: 58.33 kDa
Ligands: NAD, ZN
Released: 2 May 2001

Explore 1ICI in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

1ICI contains 32 α-helices and 24 β-strands across 2 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 16 helices, 12 β-strands

Element	Residues	Length	Sheet
β-strand	-2	1	1
α-helix	3-10	8
β-strand	15-19	5	1
α-helix	21-23	3
α-helix	25-27	3
α-helix	44-46	3
α-helix	50-55	6
α-helix	57-73	17
α-helix	78-88	11
β-strand	92-97	6	1
α-helix	103-107	5
β-strand	112-114	3	1
β-strand	117-124	8	2
β-strand	130-132	3	2
α-helix	136-138	3
β-strand	144	1	3
β-strand	151	1	3
β-strand	152-156	5	2
α-helix	157-158	2
α-helix	162-164	3
α-helix	165-177	13
β-strand	180-184	5	1
α-helix	193-195	3
α-helix	196-202	7
β-strand	206-210	5	1
α-helix	218-220	3
β-strand	223-225	3	1
α-helix	229-243	15

Chain B: 16 helices, 12 β-strands

Element	Residues	Length	Sheet
α-helix	3-10	8
β-strand	15-19	5	4
α-helix	21-27	7
α-helix	44-46	3
α-helix	50-55	6
α-helix	57-72	16
α-helix	78-88	11
β-strand	92-97	6	4
α-helix	103-106	4
β-strand	112-114	3	4
β-strand	117-124	8	5
β-strand	129	1	2
β-strand	130-132	3	5
α-helix	136-138	3
β-strand	144	1	6
α-helix	150	1
β-strand	151	1	6
β-strand	152-156	5	5
α-helix	157-158	2
α-helix	162-164	3
α-helix	165-175	11
β-strand	180-184	5	4
α-helix	193-195	3
α-helix	196-202	7
β-strand	206-210	5	4
α-helix	218-220	3
β-strand	223-225	3	4
α-helix	229-243	15

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Transcriptional regulatory protein, SIR2 family	A, B	protein	256	Archaeoglobus fulgidus	O28597 (AlphaFold model)

Sequence of entity 1 (A, B), FASTA

>1ICI_1 TRANSCRIPTIONAL REGULATORY PROTEIN, SIR2 FAMILY (chains A, B)
GSHHHHHHGSHMDEKLLKTIAESKYLVALTGAGVSAESGIPTFRGKDGLWNRYRPEELAN
PQAFAKDPEKVWKWYAWRMEKVFNAQPNKAHQAFAELERLGVLKCLITQNVDDLHERAGS
RNVIHLHGSLRVVRCTSCNNSFEVESAPKIPPLPKCDKCGSLLRPGVVWFGEMLPPDVLD
RAMREVERADVIIVAGTSAVVQPAASLPLIVKQRGGAIIEINPDETPLTPIADYSLRGKA
GEVMDELVRHVRKALS

Ligands and cofactors

ID	Name	Formula	Copies
NAD	Nicotinamide-adenine-dinucleotide	C21 H27 N7 O14 P2	2
ZN	Zinc ion	Zn	2

Primary citation

Crystal structure of a SIR2 homolog-NAD complex. Min, J., Landry, J., Sternglanz, R. et al. Cell (2001) 105:269-279. DOI 10.1016/S0092-8674(01)00317-8 · PubMed

Other PDB entries of the same protein (UniProt O28597 (AlphaFold model), which also has an AlphaFold model), best resolution first:

1M2K 1.47 Å, Sir2 homologue F159A mutant-ADP ribose complex
1M2G 1.7 Å, Sir2 homologue-ADP ribose complex
1M2J 1.7 Å, Sir2 homologue H80N mutant-ADP ribose complex
4TWI 1.79 Å, The structure of Sir2Af1 bound to a succinylated histone peptide
1M2H 1.8 Å, Sir2 homologue S24A mutant-ADP ribose complex
1M2N 2.6 Å, Sir2 homologues (D102G/F159A/R170A) mutant-2'-O-acetyl ADP ribose complex

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