9G4T: PDB entry 9G4T

Beta carbonic anhydrase CsoSCA from the Halothiobacillus neapolitanus alpha-carboxysome. Determined by electron microscopy at 2.51 Å resolution. Released 30 Jul 2025.

Method: Electron microscopy
Resolution: 2.51 Å
Organisms: Streptococcus sp. 'group G', Halothiobacillus neapolitanus
Chains: 1
Atoms: 3,589
Mol. weight: 68.36 kDa
Ligands: ZN
Released: 30 Jul 2025

Explore 9G4T in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9G4T contains 25 α-helices and 13 β-strands across 1 chain. 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: 25 helices, 13 β-strands

Element	Residues	Length	Sheet
α-helix	49-51	3
α-helix	56-74	19
α-helix	76-83	8
α-helix	92-104	13
α-helix	110-112	3
α-helix	116-119	4
α-helix	123-142	20
α-helix	155-162	8
β-strand	165-172	8	1
β-strand	173	1	2
α-helix	176-178	3
α-helix	181-186	6
β-strand	194-196	3	1
β-strand	199	1	2
α-helix	200-202	3
α-helix	206-222	17
β-strand	234-243	10	1
α-helix	254-256	3
α-helix	260-281	22
β-strand	288-296	9	1
β-strand	301-305	5	1
β-strand	318-320	3	1
α-helix	321-327	7
α-helix	333-349	17
α-helix	352-354	3
α-helix	362-386	25
α-helix	392-395	4
β-strand	401-405	5	3
β-strand	417-420	4	3
α-helix	429-442	14
α-helix	444-446	3
α-helix	448-449	2
β-strand	450-458	9	3
α-helix	465-482	18
α-helix	485-489	5
β-strand	493-501	9	3
α-helix	506-507	2
β-strand	508-511	4	3

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Immunoglobulin G-binding protein G,Carboxysome shell carbonic anhydrase	A	protein	614	Streptococcus sp. 'group G', Halothiobacillus neapolitanus	O85042 (AlphaFold model), P06654 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>9G4T_1 Immunoglobulin G-binding protein G,Carboxysome shell carbonic anhydrase (chains A)
MWSHPQFEKGGGSGGGSGGSSAWSHPQFEKYKLILNGKTLKGETTTEAVDAATAEKVFKQ
YANDNGVDGEWTYDDATKTFTVTEPMSDYDIPTTENLYFQGNTRNTRSKQRAPFGVSSSV
KPRLDLIEQAPNPAYDRHPACITLPERTCRHPLTDLEANEQLGRCEDSVKNRFDRVIPFL
QVVAGIPLGLDYVTRVQELAQSSLGHTLPEELLKDNWISGHNLKGIFGYATAKALTAATE
QFSRKIMSEKDDSASAIGFFLDCGFHAVDISPCADGRLKGLLPYILRLPLTAFTYRKAYA
GSMFDIEDDLAQWEKNELRRYREGVPNTADQPTRYLKIAVYHFSTSDPTHSGCAAHGSND
RAALEAALTQLMKFREAVENAHCCGASIDILLIGVDTDTDAIRVHIPDSKGFLNPYRYVD
NTVTYAQTLHLAPDEARVIIHEAILNANRSDGWAKGNGVASEGMRRFIGQLLINNLSQID
YVVNRHGGRYPPNDIGHAERYISVGDGFDEVQIRNLAYYAHLDTVEENAIDVDVGIKIFT
KLNLSRGLPIPIAIHYRYDPNVPGSRERTVVKARRIYNAIKERFSSLDEQNLLQFRLSVQ
AQDIGSPIEEVASA

Ligands and cofactors

ID	Name	Formula	Copies
ZN	Zinc ion	Zn	1

Primary citation

Structure and encapsulation of carbonic anhydrase within the alpha-carboxysome. Ng, P.C., Adegbite, O., Li, T. et al. Proc Natl Acad Sci U S A (2025) 122:e2523723122-e2523723122. DOI 10.1073/pnas.2523723122 · PubMed

Other PDB entries of the same protein (UniProt O85042 (AlphaFold model), which also has an AlphaFold model), best resolution first:

7SMK 1.98 Å, H. neapolitanus carboxysomal rubisco/CsoSCA-peptide (1-50)complex
9SKU 2.06 Å, Cryo-EM structure of H. neapolitanus CsoSCA in reducing conditions, hexamer
7SNV 2.07 Å, H. neapolitanus carboxysomal rubisco/CsoSCA-peptide (1-50)complex
9SKX 2.08 Å, Cryo-EM structure of H. neapolitanus CsoSCA C283A/C284A inactive mutant, hexamer
9SKV 2.12 Å, Cryo-EM structure of H. neapolitanus CsoSCA in reducing conditions, dimer, major state,…
9SKR 2.13 Å, Cryo-EM structure of H. neapolitanus CsoSCA in oxidizing conditions, hexamer
9SKS 2.15 Å, Cryo-EM structure of H. neapolitanus CsoSCA in oxidizing conditions, dimer, major state,…
9SKY 2.18 Å, Cryo-EM structure of H. neapolitanus CsoSCA C283A/C284A inactive mutant, dimer, state 1
2FGY 2.2 Å, Beta Carbonic Anhydrase from the Carboxysomal Shell of Halothiobacillus neapolitanus…
9SKZ 2.22 Å, Cryo-EM structure of H. neapolitanus CsoSCA C283A/C284A inactive mutant, dimer, state 2
9SKW 2.27 Å, Cryo-EM structure of H. neapolitanus CsoSCA in reducing conditions, dimer, minor state
9SKT 2.45 Å, Cryo-EM structure of H. neapolitanus CsoSCA in oxidizing conditions, dimer, minor state

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