4L41 | pdb_00004l41

Human Lactose synthase: A 2:1 complex between human alpha-lactalbumin and human beta1,4-galactosyltransferase

• PDB DOI: https://doi.org/10.2210/pdb4L41/pdb

• Classification: Calcium Binding Protein/Transferase
• Organism(s): Homo sapiens
• Expression System: Escherichia coli BL21
• Mutation(s): Yes 


• Deposited: 2013-06-07 Released: 2013-10-02 
• Deposition Author(s): Ramakrishnan, B., Qasba, P.K.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.70 Å
• R-Value Free: 
  0.237 (Depositor), 0.237 (DCC) 
• R-Value Work: 
  0.188 (Depositor), 0.189 (DCC) 
• R-Value Observed: 
  0.190 (Depositor) 

Starting Models: experimental

Literature

Crystal Structure of Human Lactose Synthase forms a Novel 1:2 Complex between beta1,4Galactosyltransferase 1 and alpha-Lactalbumin Proteins

Ramakrishnan, B., Qasba, P.K.

To be published.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 3-mer - A2B1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content 

• Total Structure Weight: 61.27 kDa 
• Atom Count: 4,203 
• Modeled Residue Count: 518 
• Deposited Residue Count: 535 
• Unique protein chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Alpha-lactalbumin	A, C [auth B]	124	Homo sapiens	Mutation(s): 0  Gene Names: 4-galactosyltransferase, beta1, LALBA, LYZL7
UniProt & NIH Common Fund Data Resources
Find proteins for P00709 (Homo sapiens) Explore P00709  Go to UniProtKB:  P00709
PHAROS:  P00709 GTEx:  ENSG00000167531

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Beta-1,4-galactosyltransferase 1	B [auth C]	287	Homo sapiens	Mutation(s): 2  Gene Names: alpha-lactalbumin, B4GALT1, GGTB2 EC: 2.4.1.22 (PDB Primary Data), 2.4.1 (UniProt), 2.4.1.275 (UniProt), 2.4.1.38 (UniProt), 2.4.1.90 (UniProt)
UniProt & NIH Common Fund Data Resources
Find proteins for P15291 (Homo sapiens) Explore P15291  Go to UniProtKB:  P15291
PHAROS:  P15291 GTEx:  ENSG00000086062

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
SO4	E [auth C]	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L
CA	D [auth A], F [auth B]	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.70 Å
• R-Value Free:  0.237 (Depositor), 0.237 (DCC) 
• R-Value Work:  0.188 (Depositor), 0.189 (DCC) 
• R-Value Observed: 0.190 (Depositor) 

Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 62.39	α = 90
b = 65.21	β = 114.45
c = 71.72	γ = 90

Software Package:

Software Name	Purpose
HKL-2000	data collection
PHENIX	model building
PHENIX	refinement
HKL-2000	data reduction
HKL-2000	data scaling
PHENIX	phasing

Structure Validation

Entry History 

Deposition Data

• Released Date: 2013-10-02 
Deposition Author(s): Ramakrishnan, B., Qasba, P.K.

Revision History  

• Version 1.0: 2013-10-02
  Type: Initial release
  
• Version 1.1: 2023-09-20
  Changes: Data collection, Database references, Derived calculations, Refinement description
• Version 1.2: 2024-11-06
  Changes: Structure summary